Allison Transmission AT 540 Service Manual
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Allison Transmission AT 540 Service Manual

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Service
Manual
Allison Transmission
AUTOMATIC MODELS
AT 540,
AT 542(N)(R)(NFE),
AT 543,
AT 545(N)(R),
AT 1542P,
AT 1545P(N)
Division of General Motors Corporation
P.O. Box 894 Indianapolis, Indiana 46206-0894
Printed in the U.S.A.
Copyright © 1996 General Motors Corp.
SM1241EN
FEBRUARY 1996
Revision 1, 1999 April

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  • Page 1 SM1241EN Service Manual Allison Transmission AUTOMATIC MODELS AT 540, AT 542(N)(R)(NFE), AT 543, AT 545(N)(R), AT 1542P, AT 1545P(N) FEBRUARY 1996 Revision 1, 1999 April Division of General Motors Corporation P.O. Box 894 Indianapolis, Indiana 46206-0894 Printed in the U.S.A.
  • Page 2 Check with your Allison Transmission service outlet for the currently applicable publica- tion. Additional copies of this publication may be purchased from authorized Allison Transmission service outlets. Look in your telephone directory under the heading of Transmissions — Truck, Tractor, etc.
  • Page 3 It is, however, important to understand that these Warnings and Cautions are not exhaustive. Allison Transmission could not possibly know, evaluate, and advise the service trade of all conceivable ways in which service might be done or of the possible hazardous consequences of each way.
  • Page 4 LIST OF WARNINGS This manual contains the following warnings — IT IS YOUR RESPONSIBILITY TO BE FAMILIAR WITH ALL OF THEM. • When checking the transmission fluid level, be sure that the parking brake and/or emergency brakes are set and properly engaged, and the wheels are blocked.

  • Page 5: Table Of Contents

    TABLE OF CONTENTS Paragraph Page Paragraph Page Section 1. GENERAL INFORMATION 2–10. FIRST CLUTCH a. Description ..... . . 2–4 1–1.
  • Page 6 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS Paragraph Page Paragraph Page 2–19. TORQUE PATHS THROUGH 3–10. TRANSMISSION FLUID AND FILTER TRANSMISSION CHANGE PROCEDURES a. Disassembly ..... . 3–7 a.
  • Page 7 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS Paragraph Page Paragraph Page 3–16. REPLACEMENT OF COMPONENTS g. Inspecting Bushings, Thrust Washers . . 4–11 WHILE TRANSMISSION IS IN THE h. Inspecting Oil Seals, Gaskets ..4–11 VEHICLE CHASSIS (cont’d) i.
  • Page 8 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS Paragraph Page Paragraph Page 5–3. TRANSMISSION DISASSEMBLY (cont’d) 6–7. RETARDER CONTROL VALVE BODY a. Disassembly ..... 6–12 d.
  • Page 9 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS Paragraph Page Paragraph Page 6–17. CLUTCH STACK MEASUREMENT 7–10. INSTALLATION OF MAIN CONTROL VALVE BODY, OIL FILTER, AND a. Assembly Line ....6–37 OIL PAN b.
  • Page 10 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS FOLDOUT ILLUSTRATIONS (Back of Service Manual) CROSS-SECTION VIEWS Foldout Model AT 540, 542, 543 Transmission Model AT 545, 1545 Transmission AT Transmission With Retarder SCHEMATIC VIEW Foldout Input Retarder — OFF Input Retarder — 50% Capacity Input Retarder —...

  • Page 11: Section 1. General Information

    Service organizations and individuals are encour- aged to contact their local Allison Transmission (2) Because of similarities of all models, in- Distributor for information and guidance on any of structions apply generally to all models.
  • Page 12 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS SHIPPING BRACKET BREATHER GOVERNOR COVER WELDED MODULATOR TORQUE RETAINER SELECTOR CONVERTER SHAFT ASSEMBLY OIL PAN (NOT SEPARABLE) H01341 Figure 1–1. AT 1545 Automatic Transmission — Left-Front View BREATHER BRAKE MOUNTING RETARDER CONTROL VALVE ASSEMBLY OUTPUT SHAFT OIL FILLER TUBE PORT...
  • Page 13 GENERAL INFORMATION TORQUE CONVERTER RETAINING STRAP GOVERNOR COVER MODULATOR RETAINER SELECTOR SEPARABLE SHAFT TORQUE CONVERTER OIL PAN H02875 Figure 1–3. AT 543 Automatic Transmission — Left-Front View BREATHER BRAKE MOUNTING PTO COVER OIL FILLER OUTPUT SHAFT DRAIN PLUG NAMEPLATE H02876 Figure 1–4.

  • Page 14: General Description

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS fluid coupling and a torque multiplier. AT 1500 Series transmissions also include a lockup clutch in the DIVISION OF torque converter assembly. GENERAL MOTORS CORPORATION INDIANAPOLIS Planetary Gearing, Clutches. Ratios for four INDIANA forward speeds and reverse are established by plane- SERIAL NO.
  • Page 15 GENERAL INFORMATION Table 1–1. Specifications and Data (cont’d) INPUT RATINGS — AT 1542 GASOLINE Value General Truck & Transit & Airport Inner City & Parameter Motorhome School Bus Unit Road Sweeper Shuttle Bus Shuttle Bus Input Speed Maximum full load governed speed 4400 4400 4400...
  • Page 16 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS Mounting: Engine ........... SAE 3 automotive flywheel housing with flexplate drive Vehicle .
  • Page 17 Number of elements ........3 Stall torque ratio: AT 540 AT 542...
  • Page 18 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS NOTES 1–8 Copyright © 1996 General Motors Corp.

  • Page 19: Section 2. Description And Operation

    SAE size 3 flange. This flange is bolted to the rear of the engine. (3) AT 540, 542, 545, 1542, or 1545 Series torque converter 1 (Foldout 7,B) is a closed, welded To Vehicle. Two ⁄...

  • Page 20: Oil Pump Assembly

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS stator in the same direction as the turbine and pump. (2) The pump gears draw transmission fluid At this point, torque multiplication stops and the con- from the sump. When the flow of fluid fills all the re- verter becomes, in effect, a fluid coupling.

  • Page 21: Fourth Clutch

    DESCRIPTION AND OPERATION (3) When the converter turbine rotates and (2) When hydraulic pressure is directed to the forward clutch is applied, the transmission main the piston cavity in housing 13, piston 8 compresses shaft is rotated. This drives the transmission gear set, plates 3 and 4 against backplate 2 or against retarder and drives the output shaft in any forward range.

  • Page 22: Operation Of Second Clutch

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS and fourth clutch housing 13 (Foldout 9,A) to the (2) When hydraulic pressure is directed to transmission housing, stopping rotation. Since housing the first clutch piston cavity, piston 9 (Foldout 10,B) 13 is splined to sun gear shaft 3 (Foldout 10,A), the compresses clutch plates 3 and 4 against backplate 2.

  • Page 23: Speedometer Drive/Speed Sensor Wheel

    DESCRIPTION AND OPERATION 2–12. SPEEDOMETER DRIVE/SPEED 2–14. MODULATOR SENSOR WHEEL Vacuum Modulator (Foldout 12,A) Description (Foldout 12,B) (1) Vacuum modulator 26 is calibrated and (1) The speedometer drive consists of drive sealed at the factory. gear 2 and provision for mounting the driven gear as- sembly in the transmission housing.

  • Page 24: Oil Pan And Filter

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS 2–15. OIL PAN AND FILTER (2) A cross-section of the AT 542/545R is shown on Foldout 3. The main retarder components internal to the transmission are front stator 1 (Foldout Description (Foldout 12,B) 8), the rotor which is a part of forward clutch housing (1) Oil pan 26 or 33 is a pressed steel assem- 14, and rear stator 35.

  • Page 25: Main Control Valve Assembly

    DESCRIPTION AND OPERATION (5) The retarder priority valve allows the 2–17. MAIN CONTROL VALVE regulator valve to feed the retarder if transmission ASSEMBLY fluid pressure is at an acceptable level. This is done to Main control valve body assembly 1 (Foldout 11) in- prevent the apply of the retarder from occurring if cludes valves, springs, and other components which main pressure is at a low enough level that the trans-...

  • Page 26: Converter-In (Yellow), Converter-Out (Orange), Lubrication (Green) Circuits

    After S/ (1) Governor feed is main pressure directed N 34500 (AT 540, 543 models) and for all other AT to the governor valve. The governor controls the po- models, the trimmer regulator valve and the priority sition of the governor valve, which determines the valve are also in the main-pressure circuit.

  • Page 27: Clutch Circuits

    DESCRIPTION AND OPERATION ulator pressure causes a downshift if governor pressure (2) Hold regulator pressure at each shift sig- alone will not hold the valve upward against spring nal valve will push the modulator valve upward, and force. hold the shift valve down against governor pressure. Thus, when hold regulator pressure is present, an up- shift can occur at that shift signal valve only with ex- (4) For the earlier models main-pressure reg-...

  • Page 28: Trimmer Valves

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS and the selector valve is shifted to 1 (Drive 1), the maximum value. The plug remains downward, against transmission will not immediately shift to first range. stop, until clutch released. Instead, it will shift 4–3–2–1 as speed decreases (it will remain in fourth range if speed is not decreased (4) When the transmission is shifted into re- sufficiently to allow an automatic downshift).

  • Page 29: Torque Paths Through

    DESCRIPTION AND OPERATION FOURTH CLUTCH TORQUE FORWARD CLUTCH CONVERTER THIRD CLUTCH PTO GEAR ASSEMBLY SECOND CLUTCH FIRST CLUTCH OUTPUT SHAFT CLUTCH APPLIED TORQUE PATH TURBINE SHAFT MAIN SHAFT SUN GEAR SHAFT AT 1500 Series models include a lockup clutch, not active in neutral V02877 Figure 2–1.

  • Page 30: First-Range Operation

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS TORQUE FORWARD CLUTCH FOURTH CLUTCH CONVERTER PTO GEAR THIRD CLUTCH ASSEMBLY SECOND CLUTCH FIRST CLUTCH OUTPUT SHAFT CLUTCH APPLIED TORQUE PATH TURBINE SHAFT MAIN SHAFT SUN GEAR SHAFT AT 1500 Series models include a lockup clutch, not active in first range V02878 Figure 2–2.

  • Page 31: Second-Range Operation

    DESCRIPTION AND OPERATION TORQUE FORWARD CLUTCH FOURTH CLUTCH CONVERTER PTO GEAR THIRD CLUTCH ASSEMBLY SECOND CLUTCH FIRST CLUTCH OUTPUT SHAFT CLUTCH APPLIED TORQUE PATH TURBINE SHAFT MAIN SHAFT SUN GEAR SHAFT AT 1500 Series models include a lockup clutch, not active in second range V02879 Figure 2–3.

  • Page 32: Third-Range Operation

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS TORQUE FORWARD CLUTCH FOURTH CLUTCH CONVERTER PTO GEAR THIRD CLUTCH ASSEMBLY SECOND CLUTCH FIRST CLUTCH OUTPUT SHAFT CLUTCH APPLIED TORQUE PATH TURBINE SHAFT MAIN SHAFT SUN GEAR SHAFT AT 1500 Series models include a lockup clutch, active in third range V02880 Figure 2–4.

  • Page 33: Fourth-Range Operation

    DESCRIPTION AND OPERATION TORQUE FORWARD CLUTCH FOURTH CLUTCH CONVERTER PTO GEAR THIRD CLUTCH ASSEMBLY SECOND CLUTCH FIRST CLUTCH OUTPUT SHAFT CLUTCH APPLIED TORQUE PATH TURBINE SHAFT MAIN SHAFT SUN GEAR SHAFT AT 1500 Series models include a lockup clutch, active in fourth range V02881 Figure 2–5.

  • Page 34: Reverse Operation

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS TORQUE FORWARD CLUTCH FOURTH CLUTCH CONVERTER PTO GEAR THIRD CLUTCH ASSEMBLY SECOND CLUTCH FIRST CLUTCH OUTPUT SHAFT CLUTCH APPLIED TORQUE PATH TURBINE SHAFT MAIN SHAFT SUN GEAR SHAFT AT 1500 Series models include a lockup clutch, not active in reverse V02882 Figure 2–6.

  • Page 35: Section 3. Preventive Maintenance

    Section 3 – PREVENTIVE MAINTENANCE 3–1. SCOPE hydraulic power, it is important that the proper fluid level be maintained at all times. If the fluid level is too (1) This section outlines the routine and pe- low, the converter and clutches will not receive an ade- riodical procedures required to maintain the transmis- quate supply of fluid.

  • Page 36: Transmission Fluid Level Check Procedure

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS TRANSMISSION TRANSMISSION OIL PAN OIL PAN SPLITLINE SPLITLINE TRANSMISSION OIL PAN SPLITLINE 0.50 in. 0.50 in. (12.7 mm) (12.7 mm) 0.50 in. (12.7 mm) 2.25 in. 2.00 in. 1.00 in. (50.8 mm) (57.1 mm) (25.4 mm) 1.50 in.

  • Page 37: Cold Check

    180–220°F (82–104°C) converter- facturer. Consult your Allison Transmission dealer or out temperature). Shift to D (Drive) and then to R (Re- distributor before using other fluid types; fluid types verse) to fill the hydraulic circuits with fluid.

  • Page 38: Transmission Fluid And Filter Change Intervals

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS evidence of coolant, check the cooler (heat exchanger) CAUTION: for leakage between the coolant and fluid areas. Fluid Disregarding minimum fluid temperature limits in the coolant side of the cooler (heat exchanger) is an- can result in transmission malfunction or re- other sign of leakage.
  • Page 39 PREVENTIVE MAINTENANCE PREVENTIVE MAINTENANCE Table 3–2. Transmission Fluid and Filter Change Intervals Transmission Internal Sump and External Fluid Change Application Governor Filters Auxiliary Filter** AT 500 Series Paper Filter: Paper Filter in Shallow Pan (4.0 inches) After first 5000 miles (On-Highway) 25,000 miles (40 000 km) or Deep Pan (5.3 inches):...
  • Page 40 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS RADIATOR FROM COOLER ENGINE TO COOLER TRANSMISSION TRANSMISSION FLUID FROM COOLER NAMEPLATE TYPICAL COOLER AUXILIARY FILTER TRANSMISSION FLUID TO COOLER V03129 Figure 3–4. Installation of Auxiliary Filter (Models Without Retarder) (3) If any doubt exists about the clean-up of (6) Install the filter into the line from the the cooler, replace the cooler.

  • Page 41: Transmission Fluid And Filter Change Procedures

    PREVENTIVE MAINTENANCE PREVENTIVE MAINTENANCE 3–10. TRANSMISSION FLUID AND CAUTION: FILTER CHANGE PROCEDURES Do not use gasket-type sealing compounds, fi- brous greases, or nonsoluble, vegetable-base Disassembly (Foldout 12,B) cooking compounds any place inside the trans- mission or where they could be flushed into the (1) The transmission should be at operating transmission hydraulic system.

  • Page 42: Breather

    NOTE: Except for Dimension A, the oil pan in Figure 3–5 does not represent all AT oil pan configurations. V03098 Figure 3–5. Measuring the Length of Oil Pan Boss to Identify Torque Requirements Allison Transmission Allison Transmission Next Transmission Next Transmission Internal...

  • Page 43: Linkage

    PREVENTIVE MAINTENANCE PREVENTIVE MAINTENANCE 3–13. ADJUSTMENT OF SHIFT POINTS NEOPRENE SHROUD NOTE: Transmission shift points cannot be satisfactorily adjusted if the transmission has the wrong governor installed. Check the three-digit code on the head of the governor with the code shown in the Allison Parts Catalog (SA1235) for the governor listed for EARLIER MODELS LATER MODELS...

  • Page 44: Checks Before Adjusting Shift Points

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS Checks Before Adjusting Shift Points NOTE: If all full throttle upshift points are too low by ap- (1) When calibration is to be made during a proximately the same amount, check adjustment of road test or on a test stand, certain preparations must the modulator external linkage.
  • Page 45 PREVENTIVE MAINTENANCE PREVENTIVE MAINTENANCE Table 3–4. Hold Regulator Pressure Pressure Valve Body Spring No. Color Code 2400 6836785 White 39–43 269–296 2600 6837952 Green 44–48 303–331 2600/3000 Hold 6836977 Orange 44–48 303–331 2700/2800 Hold 6837953 Blue 46–50 317–345 2800 6837953 Blue 46–50 317–345...
  • Page 46 Table 3–7. AT 500 Shift Points — Models With S/N 3210302450 and Before (Without Lockup) Engine Governed Speed — rpm 2400 2400 2600 2800 3000 3200 3400 3600 3800/4000 AT 545 Parts Catalog Valve Body Group Throttle Transmission Output Speed (rpm) at Start of Shift Range Position Shift...
  • Page 47 Table 3–8. AT 500 Shift Points — Models After S/N 3210302450 (Without Lockup) Engine Governed 2400 2600 2800 3000 3200 3400 3600 3800 4000 Speed — rpm AT 545 Parts Catalog Valve Body J, R G, M F, H, K, L E, N, S C, Q Group...
  • Page 48 Table 3–9. AT 1500 Shift Points (With Lockup) Engine Governed Speed — rpm 2400 2600 2800 3000 4000 AT 1542 AT 1545 Y, AE W, X, AD, AT 1500 Parts Catalog Valve Body Group Throttle Position Range Shift Transmission Output Speed (rpm) at Start of Shift 1–2* 580–640 595–655...

  • Page 49: Transmission Stall Test And Neutral Cool-Down Check

    PREVENTIVE MAINTENANCE PREVENTIVE MAINTENANCE 3–14. TRANSMISSION STALL TEST AND (6) Block the vehicle wheels. NEUTRAL COOL-DOWN CHECK (7) Start the engine and let the transmission sump warm to normal operating temperature 160–200°F Purpose (71–93°C). (1) Stall testing is performed to determine (8) Perform a hot check of the transmission whether a power complaint is due to an engine prob- fluid level and adjust as necessary.

  • Page 50: Stall Test Procedures - Vehicles With Smoke-Controlled Engines

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS Stall Test Procedures — Vehicles With (1) If the engine stall speed is more than 150 Smoke-Controlled Engines rpm below the stall speed specified by the engine man- ufacturer, an engine problem is indicated, such as the need for a tune-up.

  • Page 51: Storage, One Year - With Transmission Fluid

    PREVENTIVE MAINTENANCE PREVENTIVE MAINTENANCE (3) Seal all openings and the breather with CAUTION moisture-proof tape. Never maintain the stall condition for more than 30 seconds at any one time because of the rapid (4) Coat all exposed, unpainted surfaces rise in fluid temperature. Do not let the con- with preservative grease such as petrolatum (MIL-C- verter-out fluid temperature exceed 300°F 11796, Class 2).

  • Page 52: Replacement Of Components While Transmission Is In The Vehicle Chassis

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS (5) If the transmission was prepared for stor- lected legs with puller body J 24420-B and bolt J 24463. age with transmission fluid, it is not necessary to drain Engage each puller leg into the bearing by placing the and refill the transmission with new transmission fluid.

  • Page 53: Installation Of Output Shaft Bearing

    PREVENTIVE MAINTENANCE PREVENTIVE MAINTENANCE Installation of Output Shaft Bearing 3–17. TROUBLESHOOTING — BEFORE and Snapring REMOVAL OR OPERATION OF TRANSMISSION (1) Clean the bearing bore. Make sure snapring 9 (Foldout 12,A) is seated in its groove and is Visual Inspection. Do not operate the vehicle not damaged.
  • Page 54 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS (3) Modulator comparison check. Using a • Holding the modulators in a horizontal posi- comparison gauge (Figure 3–10), compare the load of a tion, bring them together under pressure until known good modulator with the assembly in question. either modulator sleeve end just touches the line in the center of the gauge.

  • Page 55: Troubleshooting - Before

    PREVENTIVE MAINTENANCE PREVENTIVE MAINTENANCE Hydraulic Pressure Checking Procedures ENDS TO BE SQUARE WITHIN ⁄ WARNING! (0.40 mm) Observe safety precautions during hydraulic ⁄ in. (131.03 mm) TO ⁄ in. (9.53 mm) pressure check procedures. All personnel must SCRIBED ROUND OR FLAT STOCK LINE stand clear of the vehicle.
  • Page 56 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS MODULATOR ACCESS (MECHANICAL OR VACUUM) MAIN PRESSURE H02887 Figure 3–11. Transmission Check Points BREATHER TO COOLER FROM COOLER (AUXILIARY FILTER) LOCKUP PRESSURE (AT 1500 SERIES) OIL FILL TUBE REVERSE SIGNAL PRESSURE DRAIN PLUG H02888 Figure 3–12.
  • Page 57 PREVENTIVE MAINTENANCE PREVENTIVE MAINTENANCE FROM PRIMARY COOLER TRANSMISSION “TO COOLER” PORT TRANSMISSION “FROM COOLER” PORT WIRING HARNESS CONNECTOR CONNECTS TO TRANSMISSION “MAIN” PRESSURE TAP (OPPOSITE SIDE OF TRANSMISSION) RETARDER VALVE BODY FIRST CLUTCH PRESSURE TAP (NEAR SPEEDOMETER PROVISION) DIVISION OF DIVISION OF GENERAL MOTORS GENERAL MOTORS...
  • Page 58 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS Table 3–11. Main Pressure Check Procedure (Models With Modulated Main Pressure) WARNING! Observe safety precautions during hydraulic pressure check procedures. All personnel must stand clear of the vehicle. Take precautions against movement of the vehicle. Be sure that gauges (vacuum, pressure, tachometer) have extended lines so that they can be read from inside the vehicle.
  • Page 59 PREVENTIVE MAINTENANCE PREVENTIVE MAINTENANCE Table 3–13. Troubleshooting Chart Problem Probable Causes Suggested Remedies A. Abnormal Automatic Shifts Shifts occurring at too high speed Governor valve malfunctioning Clean or replace governor screen (stuck). and/or governor. The governor may be disassembled for cleaning and inspection only if the kit consisting of two governor weight pins and cover gasket is available.
  • Page 60 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS Table 3–13. Troubleshooting Chart (cont’d) Problem Probable Causes Suggested Remedies A. Abnormal Automatic Shifts (cont’d) Shifts occurring at too low speed — Governor spring weak or missing. Replace governor. Refer to Para- full throttle graphs 5–3e and 7–10a.
  • Page 61 PREVENTIVE MAINTENANCE PREVENTIVE MAINTENANCE Table 3–13. Troubleshooting Chart (cont’d) Problem Probable Causes Suggested Remedies A. Abnormal Automatic Shifts (cont’d) Rough shifting (cont’d) Trimmer valves sticking (broken Replace or rebuild main control spring). valve body assembly. Refer to Para- graph 6–6. Control valves sticking.
  • Page 62 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS Table 3–13. Troubleshooting Chart (cont’d) Problem Probable Causes Suggested Remedies B. Abnormal Activities or Responses (cont’d) Vehicle moves backward in neutral Shift selector linkage out of adjust- Repair or replace linkage.* ment. Fourth clutch failed and dragging. Rebuild fourth clutch.
  • Page 63 PREVENTIVE MAINTENANCE PREVENTIVE MAINTENANCE Table 3–13. Troubleshooting Chart (cont’d) Problem Probable Causes Suggested Remedies A. Abnormal Stall Check Speed (cont’d) High stall speeds (cont’d) Fourth clutch (reverse) slipping. Rebuild fourth clutch. Refer to Para- graph 6–11. Low stall speeds Engine not performing efficiently Refer to engine manufacturer’s man- (may be due to plugged or restricted ual or vehicle service manual.
  • Page 64 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS Table 3–13. Troubleshooting Chart (cont’d) Problem Probable Causes Suggested Remedies C. Low Pressure Low main pressure in all ranges Low fluid level. Add fluid to the proper level. Refer to Paragraphs 3–4 through 3–10. Filter element(s) clogged.
  • Page 65 PREVENTIVE MAINTENANCE PREVENTIVE MAINTENANCE Table 3–13. Troubleshooting Chart (cont’d) Problem Probable Causes Suggested Remedies D. Slippage † /** Excessive slippage and clutch chat- Clutch slipping in that range. Rebuild the specific clutch that is ter in only one range slipping and replace piston seals. Excessive fluid leakage in range Overhaul clutch and piston assem- piston seals.
  • Page 66 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS Table 3–13. Troubleshooting Chart (cont’d) Problem Probable Causes Suggested Remedies A. Slippage † /** (cont’d) Slippage in first range and in First clutch slipping. Overhaul clutch and replace piston reverse; proper function in other seals.
  • Page 67 PREVENTIVE MAINTENANCE PREVENTIVE MAINTENANCE Table 3–13. Troubleshooting Chart (cont’d) Problem Probable Causes Suggested Remedies A. Overheating in all Ranges (cont’d) Overheating in all ranges (cont’d) Broken parts in torque converter.†† Replace or repair torque converter assembly. Refer to Paragraph 6–4.*** Aerated fluid.
  • Page 68 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS Table 3–13. Troubleshooting Chart (cont’d) Problem Probable Causes Suggested Remedies K. Dirty Transmission Fluid Dirty fluid Failure to change fluid at proper Change fluid and install new filter or interval. element(s). Refer to Paragraph 3–10. Excessive heat.

  • Page 69: Section 4. General Overhaul Information

    Section 4 – GENERAL OVERHAUL INFORMATION 4–1. SCOPE NOTE: This section provides general information for over- The transmission holding fixture (Figure 5–1) may haul, cleaning, inspection, and general assembly pro- be mounted on the work table. cedures for the transmission. It provides illustrations and explanations for the fabrication of improvised tooling.

  • Page 70: Special Tools

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS V03103 Figure 4–2. Special Tools (1 thru 34) 4–2 Copyright © 1996 General Motors Corp.
  • Page 71 GENERAL OVERHAUL INFORMATION V03109 Figure 4–3. Special Tools (35 thru 45) Copyright © 1996 General Motors Corp. 4–3...
  • Page 72 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS V03110 Figure 4–4. Special Tools (46 thru 77) 4–4 Copyright © 1996 General Motors Corp.
  • Page 73 GENERAL OVERHAUL INFORMATION Table 4–1. Special Tools Tool No. Figure Item Description Ref. Paragraph J 3289-20 4–2 Transmission holding fixture base (used with 5–3 a J 23642-01) J 3453 4–4 Universal yoke and flange holder J 5959-1 4–4 Dial indicator (used with J 5959-3, J 5959-7, 6–3 b J 7872-2, J 7872-3, and J 24602) J 5959-3...
  • Page 74 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS Table 4–1. Special Tools (cont’d) Tool No. Figure Item Description Ref. Paragraph J 23631 4–2 Output shaft seal installer 3–16 g , 7–9 a J 23632-01 4–2 Spacer selection gauge 7–6 a J 23633 4–2 Thrust washer selection gauge bar 7–8 a...
  • Page 75 GENERAL OVERHAUL INFORMATION Table 4–1. Special Tools (cont’d) Tool No. Figure Item Description Ref. Paragraph J 25356 4–4 Front pump bushing installer 6–9 d J 25587-01* 4–3 Planetary rebuilding kit 6–16 b , d J 25587-1 4–3 Swaging fixture 6–16 J 25587-2 4–3 Pin remover and installer adapter...

  • Page 76: Mechanic's Tools, Shop Equipment

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS Table 4–1. Special Tools (cont’d) Tool No. Figure Item Description Ref. Paragraph J 33184*** 4–3 Fourth clutch hub drilling fixture J 33410 4–3 Neutral start switch wrench 7–12e J 34127 4–3 Selective snapring gauge for center support (used 7–5b with J 23717-C) J 34814...

  • Page 77: Replacement Parts

    GENERAL OVERHAUL INFORMATION • A hot plate or heating equipment (for heat- 4–5. CLEANING AND INSPECTION ing bearings or other interference-fit parts to aid assembly) NOTE: A press for disassembly and assembly of • detailed inspection criteria, refer spring-loaded clutches, valves, and interfer- GN1948EN, AT Technician's Guide.

  • Page 78: Inspecting Bearings

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS (2) If the bearings are particularly dirty or (3) Do not lay bearings on a dirty bench; filled with hardened grease, soak them in mineral spir- place them on clean, lint-free paper. its before trying to clean them. (4) If assembly is not to be completed at (3) Before inspection, lubricate the bearings once, wrap or cover the exposed bearings with clean...

  • Page 79: Inspecting Bushings, Thrust Washers

    GENERAL OVERHAUL INFORMATION (8) Inspect the hydraulic circuit tracks in the (2) Inspect thrust washers for distortion, valve bod(ies) and transmission housing main control scores, burrs, and wear. Replace if defective or worn. valve body mounting surface for porosity, broken lands, cracks, dirt, and land surface imperfections.

  • Page 80: Inspecting Gears

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS Inspecting Gears Inspecting Clutch Plates (1) Inspect friction-faced steel plates (inter- nal-splined plates) for burrs, imbedded metal particles, CAUTION: severely pitted faces, excessive wear, cone, cracks, dis- Do not attempt to correct the governor driven tortion, and damaged spline teeth.

  • Page 81: Assembly Procedures

    GENERAL OVERHAUL INFORMATION 4–6. ASSEMBLY PROCEDURES during assembly with mating parts. The oil-soluble grease will help keep the sealrings centered in their grooves and will help protect the parts from damage. Clutches, Pistons (1) Establish clutch pack clearances prior to Lip-Type Seals (Metal-Encased) assembly.

  • Page 82: Removing (Or Installing) Transmission

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS (2) If a bearing must be removed or installed Transmission Installation without a sleeve, press only on the race which is ad- (1) Use a transmission jack to raise the trans- jacent to the mounting surface. If a press is not mission into mounting position.

  • Page 83: Section 5. Disassembly Of Transmission

    Section 5 – DISASSEMBLY OF TRANSMISSION 5–1. SCOPE assembly 6 from retarder control valve body assem- bly 18. This section covers disassembly of the transmission into subassemblies. (4) Remove gasket 16, separator plate 17, and a second gasket 16. 5–2. GENERAL INFORMATION (5) Refer to Paragraph 6–7 for rebuild of the retarder control valve body assembly.

  • Page 84: Removal Of Torque Converter

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS Removal of Torque Converter TORQUE CONVERTER (1) Remove the bolts and nuts that hold the ASSEMBLY converter retaining device to the transmission housing. (2) Attach a three-strand sling to the torque STATOR converter. Lift the converter from the transmission TURBINE SHAFT SHAFT housing and place it on a work table (Figure 5–2).

  • Page 85: Removal Of Governor

    DISASSEMBLY OF TRANSMISSION OIL PAN VALVE ACTUATING ROD (EARLIER MODELS) SEALRING SCREW (21) GOVERNOR BOLT, ⁄ -18 x ⁄ . (4) VACUUM COVER MODULATOR GASKET H02895 GOVERNOR Figure 5–4. Removing Vacuum Modulator ASSEMBLY H02896 (3) Firmly holding the end of the wrench op- Figure 5–5.
  • Page 86 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS (2) On later models, remove the two 3 inch main control valve body (Figure 5–7) by lifting up- bolts (Figure 5–7) that retain the first (reverse) clutch ward on the body and the attached feed tubes. feed tube.

  • Page 87: Removal Of Pump

    DISASSEMBLY OF TRANSMISSION Removal of Pump (5) Install the assembled slide hammers into the pump. Hammer upward with the slide hammers to (1) Rotate the transmission so that the torque loosen the pump assembly. When free, lift the pump as- converter end is upward.

  • Page 88: Removal Of Forward Clutch And Turbine Shaft

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS (7) Remove two hook-type sealrings 38 (2) Lift the front stator from the forward (Foldout 7,B) and thrust washer 37 from the pump as- clutch assembly (Figure 5–13). sembly. Refer to Paragraph 6–7 for rebuild of the (3) Remove thrust washer 31 (Foldout 8) pump assembly.

  • Page 89: Removal Of Fourth Clutch

    DISASSEMBLY OF TRANSMISSION (4) Remove the retarder housing assembly m. Removal of Third Clutch (Figure 5–14). Refer to Paragraph 6–10 for rebuild. NOTE: Removal of Fourth Clutch • For models without retarder, proceed with Step (1). (1) Grasp the spring retainer on the fourth For models with retarder, skip Steps (1) and (2) •...

  • Page 90: Removal Of Planetary Gearing

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS INTERNAL-SPLINED PLATE (3) J 23643 EXTERNAL-TANGED PLATE (3) CENTER SUPPORT SNAPRING ASSEMBLY H02905 Figure 5–18. Removing Center Support Assembly SECOND CLUTCH PLANETARY SNAPRING CENTER SUPPORT GEAR UNIT ASSEMBLY H02904 Figure 5–17. Removing Third Clutch Plates CAUTION: THRUST The center support is fitted to the transmission...

  • Page 91: Removal Of Second Clutch

    DISASSEMBLY OF TRANSMISSION MACHINED TRANSMISSION SURFACE MAIN SHAFT SECOND CLUTCH SNAPRING PLANETARY GEAR UNIT H02907 H02908 Figure 5–21. Removing Second Clutch Snapring Figure 5–20. Removing Planetary Gear Unit (4) Governor drive gear 1 (Foldout 12,B), speedometer drive gear 2 or speed sensor wheel 9, and BACKPLATE spacer 3 may come out with the gear unit, or may stay in the transmission.

  • Page 92: Removal Of Output Shaft Seal And Bearing

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS SNAPRING SNAPRING RETAINER BEARING J 23630-02 PISTON J 23630-3 H02911 H02910 Figure 5–24. Removing Output Shaft Bearing Snapring Figure 5–23. Removing First Clutch Spring Retainer Snapring Removal of Output Shaft Seal and Bearing (1) Rotate the transmission so that the output WARNING! is upward.

  • Page 93: Section 6. Rebuild Of Subassemblies

    (5) Set the dial to read zero and lift J 24602 as far as possible. CAUTION: Allison Transmission Division GM recommends only genuine Allison torque converters for use with any AT 500, 1500 Series Allison transmis- sions. Any transmission damage that may occur...

  • Page 94: Leak Check

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS (6) The dial indicator reading must not ex- (4) Release the air from the torque converter ceed the values listed in Table 6–1. If the converter end by pushing on the valve stem in the air fitting on the play exceeds the value listed, replace the torque con- center body.
  • Page 95 REBUILD OF SUBASSEMBLIES (3) Remove the front cover (Figure 6–4). (7) Position the stator assembly front down- Remove the front cover sealring. ward, and remove the freewheel roller race by rotating it clockwise while lifting. (4) Remove two bearing races, bearing, and (8) Remove ten rollers 26 (Foldout 7,A) and bearing spacer (Figure 6–5).

  • Page 96: Replacement Of Needle Bearing Assembly In Stator Assembly

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS (10) Remove the needle bearing assembly and (2) Place a new bearing assembly into the bearing race from the converter pump (Figure 6–8). aluminum bore of the stator. Using bearing installer tool J 23549 and handle J 24202-4, install the thrust (11) Flatten the corners of lockstrips 29 bearing (Figure 6–9).
  • Page 97 REBUILD OF SUBASSEMBLIES BEARING 0.035 in. (0.89 mm) 0.025 in. (0.64 mm) VIEW AT STATOR Assembly load to be DEEP POCKET applied in this area Assemble with on outer shell only cam pockets in DIRECTION OF position shown FREEWHEEL ROTATION ENLARGED VIEW OF CROSS-SECTION ENLARGED VIEW...
  • Page 98 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS (16) Install twenty-four nuts to retain the con- THRUST WASHER RIVET verter cover (Figure 6–3). Tighten four of the nuts, at 90 degree intervals, to 10 lb ft (14 N . m). Then, tighten STATOR CAM all the nuts to 19–23 lb ft (26–31 N .

  • Page 99: Governor

    REBUILD OF SUBASSEMBLIES DEPTH MICROMETER NEEDLE THRUST DEPTH MICROMETER BEARING, BAR, 1 x 1 x 24 TWO RACES BLOCK BAR, 1 x 1 x 24 BLOCK BLOCK CONVERTER COVER H02926 Figure 6–13. Measuring Dimension A for Selection of BLOCK Converter Spacer (AT 543) CONVERTER PUMP CONVERTER TURBINE H02929...

  • Page 100: Main Control Valve Body

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS consisting of two governor weight pins and the cover gasket is available. (2) Follow the directions furnished with the kit to disassemble the governor. Assembly (Foldout 12,A) GOVERNOR FEED (Must open 0.020 in. (1) Assemble the governor as outlined in the (0.51 mm) min) GOVERNOR directions furnished with the governor service kit.
  • Page 101 REBUILD OF SUBASSEMBLIES clutch trimmer valve 21; and springs 31 and 32 (if View A, Figure 6–19, discard the valve and replace it present), stop 33, plug 30, and fourth clutch trimmer with a new valve at reassembly. valve 29. For models that do not have spring 32, dis- card spring 31 and install new springs 31 and 32.
  • Page 102 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS (17) Restrain stop 74 and remove retainer pin (7) If removed, install spring 27 into Bore P 75. Remove stop 74, spring 73, and 3–4 relay valve 72. (Figure 6–20). Into the same bore, install stop 26 Valve stop 74 replaces two parts used in earlier mod- (Foldout 11) and accumulator valve 28.
  • Page 103 REBUILD OF SUBASSEMBLIES Figure 6–20. Control Valve Body Assembly — With Components Installed Copyright © 1996 General Motors Corp. 6–11...
  • Page 104 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS (14) Install hold regulator valve 46 into Bore L (Figure 6–20). Into the same bore, install spring 47 (Foldout 11) and valve stop 48. Prior to transmission MODULATOR VALVE S/N 113786, install valve plug 49. Beginning with GOVERNOR CHECK VALVE BALL (EARLIER MODELS) transmission S/N 113786, install washer 50 and ad-...

  • Page 105: Assembly

    REBUILD OF SUBASSEMBLIES (3) Restrain plug 27 and remove pin 22. 6–8. TRANSFER PLATE ASSEMBLY (Retarder Models) (Foldout 13) (4) Remove plug 27, capacity pin 26, spring 25, and regulator valve 24. Disassembly (1) Remove snapring 9 from feedthrough WARNING! seal 10.

  • Page 106: Oil Pump And Front

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS (6) If present, remove pipe plug 15 (at the temperature sending unit location) or, if present, re- move the temperature sending unit. Assembly (1) If removed, install ⁄ -14 pipe plug 15. Tighten the plug to 16–20 lb ft (22–27 N . m). (2) Place solenoids 7 in place in transfer plate 14 and install pins 13.
  • Page 107 REBUILD OF SUBASSEMBLIES (3) Remove five bolts 28 and 29 from front support 16. (4) Separate pump body and gear assembly 5 from front support 16. Remove pump driven gear 9 and pump drive gear 10 from pump body 8. (5) Remove sealring 4 from pump body 8.

  • Page 108: Installation Of Stator Shaft And Bushing

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS (3) Press the stator shaft into the front sup- NOTE: port to Dimension M as measured from Surface B to the end of the stator shaft (Surface L) (Figure 6–25 If stator shaft 19 does not require being re- •...

  • Page 109: Pump Gear Clearance Check

    REBUILD OF SUBASSEMBLIES (5) Coat the OD of a new non-prebored re- (1) Position oil pump body assembly 6, flat placement bushing 18 (Foldout 7,B) with Loctite ® side upward. Install drive gear 10 into pump body as- sleeve retainer, or equivalent. Install bushing 18 into sembly 6, so the internal tangs of the gear are facing the stator shaft with J 23614-A to a depth of flush to upward.

  • Page 110: Assembly

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS (5) Check the driven gear diametrical clear- DIAL INDICATOR J 26857 ance with a feeler gauge as shown in Figure 6–31. Re- place the gear if the clearance is not within 0.0055– OIL PUMP BODY 0.0085 inch (0.14–0.22 mm) on a new gear or OIL PUMP DRIVEN GEAR 0.0055–0.0089 inch (0.14–0.23 mm) on a used gear.
  • Page 111 REBUILD OF SUBASSEMBLIES (1) For models without lockup, if roller bear- NOTE: ing 23 was removed, using installer J 23615, press on For models without lockup, skip Step (7) and the lettered end of the new bearing to a depth of •...

  • Page 112: Forward Clutch And Turbine Shaft Assembly

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS (14) Install front support assembly 16 onto (16) Install bolts 28 and 29 as were removed. pump body assembly 5, aligning the bolt holes. (For different models, the length may differ). (17) Tighten all the ⁄...
  • Page 113 REBUILD OF SUBASSEMBLIES at the internal spline of the hub may occur. This wear SHIM 2 ring, the result of contact with the transmission main FORWARD SNAPRING CLUTCH HOUSING GEAR shaft, is so uniform in shape that it is often overlooked. SNAPRING Replace this hub where this condition exists.

  • Page 114: Checking Clutch Pack Clearance (Models Without Wave Plate)

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS (17) Remove spring retainer 21 (Foldout 8) Checking Clutch Pack Clearance and sixteen clutch springs 20. (Models Without Wave Plate) (18) Remove forward clutch piston 19 from the clutch housing. If necessary, turn the clutch hous- NOTE: ing over and “bump”...
  • Page 115 REBUILD OF SUBASSEMBLIES “9661” STAMPED 2.005 in. 2.043 in. (50.93 mm) (51.89 mm) EARLIER HUB LATER HUB V02945 Figure 6–38. Fourth Clutch Drive Hub Identification (5) If the clutch running clearance is not Assembly (Foldout 8) within the specified limits, remove snapring 30, fourth (1) If ball 10 or 15 was removed, place the clutch drive hub 29, and clutch plates 27 and 28.
  • Page 116 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS (8) Beginning with an external-tanged clutch CAUTION: plate, install the clutch pack established in Paragraph When installing the forward clutch snapring, do 6–9c(6) or 6–17b(3) (Figure 6–42). not allow the spring retainer to catch in the snapring groove.

  • Page 117: Assembly

    REBUILD OF SUBASSEMBLIES (12) Place PTO gear 32 onto the forward 6–12. FOURTH CLUTCH ASSEMBLY clutch housing. Be sure the chamfer on the inside di- ameter of the PTO gear is facing downward. Disassembly (Foldout 9,A) (13) Compress snapring 31 into the clutch (1) Place the fourth clutch on the work table, housing and install the PTO gear.

  • Page 118: Checking Clutch Pack Clearance

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS NOTE: NOTE: Earlier model transmissions use a piston seal on If the J 23619-01 gauge is not available, measure the fourth clutch housing 13. If present, discard the clearance between the backplate and the first clutch housing seal.

  • Page 119: Center Support Assembly

    REBUILD OF SUBASSEMBLIES (6) Repeat Steps (2), (3), (4), and (5). When CAUTION: the running clearance is within 0.0765–0.1265 inch When removing piston retainer washers, cut the (1.944–3.213 mm), remove snapring 1, clutch back- retainer washers carefully to prevent damaging plate 2, clutch plates 3 and 4, and piston.

  • Page 120: Rework Of Center Support Piston Retainer Locating Notches

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS Rework of Center Support Piston Retainer (3) Place piston 9 (Foldout 9,B) in its bore Locating Notches (Foldout 9,B) without the piston sealrings in place, with the four ejector pin bosses upward. Install piston return springs 8 in the twelve holes in third clutch piston 9.

  • Page 121: Planetary Gear Unit

    REBUILD OF SUBASSEMBLIES SUPPORT Identifying notch of bushing to show on this side of support J 24453 CENTER 90° SUPPORT 500 LB THIRD (2224 N) CLUTCH BUSHING PISTON H02955 Figure 6–50. Installing Self-Locking Retainer Washer SECTION (1) Remove front planetary sun gear 6. Press bushing flush to 0.010 in.

  • Page 122: Assembly

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS (9) Remove needle bearing assembly 32 and 0.6485 in. (16.472 mm) bearing race 33 located between output shaft 45 and 0.6475 in. (16.447 mm) rear sun gear 31. (10) Place the output shaft on a work bench in a vertical position (rear planetary carrier upward).
  • Page 123 REBUILD OF SUBASSEMBLIES (5) If the transmission being rebuilt has a (11) Install ball bearing assembly 44 over the governor drive gear with a large V slot (Figure 6–55), snapring groove end of output shaft 45. Install output install a spring pin 50 (Foldout 10,A) into the output shaft 45 (snapring groove first) into rear planetary car- shaft to a height of 0.150–0.170 inch (3.81–4.31 mm).

  • Page 124: Transmission Main Housing Assembly

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS LARGE “V” SLOT EARLIER DESIGN DEAD END SLOT LATER DESIGN END VIEW SIDE VIEW TOP VIEW V02960 Figure 6–55. Governor Drive Gear Configurations (21) Install front planetary sun gear 6, ID RETAINER SELECTOR spline chamfer (if present) downward, into the front VALVE PIN planetary carrier assembly.

  • Page 125: Assembly

    REBUILD OF SUBASSEMBLIES (5) Inspect governor support pin 12 for evi- (3) Hold selector lever 54 or 55 (Foldout dence of wear. If any wear is noted on the end or on 12,B) so the selector valve pin is facing the inside of the OD of the pin, remove the pin using pin remover the case.

  • Page 126: Inspection

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS Inspection NOTE: (1) Visually inspect the planetary carrier as- Do not disassemble the carrier assembly unless • sembly for evidence of excessive wear, indications of parts replacement is necessary. Failure of one pin- overheating, damage, or heavy metal contamination. ion requires replacement of the entire matched pinion gear set, pinion pins, and bearings.

  • Page 127: Removal Of Pinion Components

    REBUILD OF SUBASSEMBLIES Removal of Pinion Components Replacing Bushing in Front Planetary Carrier (1) Using a drill that is slightly smaller than (1) Fabricate four dummy pins to the dimen- the pinion pin diameter, drill into the swaged end on sions shown in Figure 6–60.

  • Page 128: Installation Of Pinion Components

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS (6) Using a lathe with a four jaw chuck, CAUTION: mount the carrier with Surface A facing the chuck. In- Do not put pressure on the carrier. Distortion of sert the four fabricated dummy pins (Figure 6–60) into the carrier will damage it.
  • Page 129 REBUILD OF SUBASSEMBLIES NOTE: PRESS 980–1020 LBS (4359 – 4537 N) Swaging pressure varies with the size of the pinion PLATE pins (approximately two tons for front carriers; three tons for center and rear carriers). While ap- plying pressure, rotate the pinions and feel for re- SLEEVE duction of end play.
  • Page 130 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS (2) Apply the specified load, and measure Dimension X. 1.919 in. 1.870 in. (3) From the table in Figure 6–64, select the (48.74 mm) (47.49 mm) fourth clutch piston. Use the parts measured, and the 1.909 in.
  • Page 131 REBUILD OF SUBASSEMBLIES (3) The clutch running clearance will be (2) Apply the specified load, and measure within limits when the stack thickness measurement is Dimension X. from 1.93–1.97 inch (49–50 mm). (3) From the table in Figure 6–67, select the (4) Use the parts measured when the trans- first clutch backplate.
  • Page 132 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS NOTES 6–40 6–40 Copyright © 1996 General Motors Corp. Copyright © 1996 General Motors Corp.
  • Page 133 Section 7 – ASSEMBLY OF TRANSMISSION 7–1. SCOPE (2) An initial clutch plate running clearance check may be in excess of the required dimension. Do This section covers assembly of transmission from not install a thicker backplate if excess clearance can subassemblies and parts.
  • Page 134 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS (5) Install twenty-two springs into the re- (9) For models before S/N 5071, install all cesses in the piston. Install the spring retainer onto the fourteen first clutch plates into the transmission as fol- springs (Figure 7–2).
  • Page 135 ASSEMBLY OF TRANSMISSION INTERNAL-SPLINED PLATE RING GEAR INTERNAL-SPLINED PLATE EXTERNAL-TANGED PLATE H02974 Figure 7–3. Installing First Clutch Plates Onto Rear Planetary Ring Gear (2) If the clearance is excessive (larger end (4) Backplates are stamped with identifying of gauge will pass between the snapring and the back- numbers (1, 2, 3, 4, 5 (or no mark), or 6).
  • Page 136 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS Planetary Gear Unit MAIN SHAFT NOTE: PLANETARY • Models before S/N 5071 include the rear plane- GEAR UNIT tary ring gear as part of the planetary gear unit. Proceed with Steps (1) and (2). •...
  • Page 137 ASSEMBLY OF TRANSMISSION EXTERNAL- INTERNAL- TANGED SPLINED PLATE (3) PLATE (2) SNAPRING GEAR SET CLUTCH PLATES H02980 Figure 7–9. Second Clutch Snapring Installed BACKPLATE INTERNAL- SPLINED PLATE (2) Be sure the lips of the sealrings of both pistons each face (what will be after installation) the bottom of the respective piston cavity in the center sup- port.
  • Page 138 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS (7) Install center support compressor (12) Remove the center support compressor. J 23717-C (Figure 7–10). Use two of the ⁄ -18 x 1 ⁄ inch oil pump assembly retaining bolts to retain the (13) Install two new hook-type sealrings 12 compressor.
  • Page 139 ASSEMBLY OF TRANSMISSION J 23632-01 OUTPUT SHAFT J 24352 (J 39736- 01, AT 1500 Series) J 21795-4 (J 39736- 02, AT 1500 Series) MAIN SHAFT H02983 Figure 7–12. Installing Sun Gear Shaft Retainer H02985 Figure 7–14. Measuring For Selection of Rear Bearing Spacer GOVERNOR DRIVE GEAR...
  • Page 140 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS (8) Check the end play of the transmission (11) Install spring compressor assembly output shaft as follows. J 23630-2. Tighten the ⁄ -20 x 1 ⁄ inch center bolt to 15 lb ft (20 N·m). Align the spring compressor base with the two parking brake mounting holes in the (9) Place the first clutch spring compressor transmission housing (Figure 7–17).
  • Page 141 ASSEMBLY OF TRANSMISSION (1) Beginning with an external-tanged clutch plate, alternately install three (models without re- tarder) or four (models with retarder) external-tanged APPROX. ⁄ in. (3.18 mm) and three internal-splined plates (Figure 7–19). Note the location of the three pairs of tangs and a single tang in relation to paired slots and a single slot.
  • Page 142 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS Forward Clutch and Turbine Shaft EXTERNAL-TANGED PLATE (3) – MODELS WITHOUT RETARDER (4) – MODELS WITH RETARDER Assembly (Foldout 8) INTERNAL-SPLINED PLATE (3) FOURTH CLUTCH (1) Install the thrust washer onto the hub of the forward clutch assembly, retaining it with oil-solu- ble grease (Figure 7–22).
  • Page 143 ASSEMBLY OF TRANSMISSION 7–8. INSTALLATION OF (3) Measure the distance from the top of the gauge bar to the thrust surface of the clutch housing OIL PUMP ASSEMBLY (Figure 7–25). Subtract 1.00 inch (25.4 mm) or the thickness of the gauge bar and record the difference. Selection of Front Thrust Washer Select the proper thrust washer from the following ta- (Foldout 7,B)
  • Page 144 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS Pump Assembly (Foldout 7,B) (5) Install two ⁄ -18 headless guide bolts into two opposite holes in the gasket and transmission (1) Using oil-soluble grease, install the thrust housing (Figure 7–24 or 7–28). washer selected in Paragraph 7–8a(3), onto the oil pump assembly (Figure 7–26).
  • Page 145 ASSEMBLY OF TRANSMISSION (2) Start the oil seal, lip first, squarely into NOTE: the rear bore of the transmission housing. • For models with retarder, proceed with Step (8). (3) Using installer tool J 23631, drive the oil • For models without retarder, skip Step (8) and seal into the housing until the installer seats against the proceed with Step (9).
  • Page 146 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS (2) If the anchor bolt is ⁄ -16, tighten it to (5) Install governor circuit screen 12 (Fold- 39–46 lb ft (53–62 N . m); if the anchor bolt is ⁄ -20, out 12,B) closed end first, into the valve body, at the tighten it to 67–80 lb ft (91–108 N .

  • Page 147: Filter

    ASSEMBLY OF TRANSMISSION FIRST CLUTCH FEED BOLT – LATER MODELS (16) TUBE BOLTS, 3 in. (2) BOLT – EARLIER MODELS (17) OR (18) FILTER SPACER FIRST CLUTCH TUBE INTAKE TUBE (EARLIER MODELS) FILTER SCREEN IN GOVERNOR FEED TUBE BORE GOVERNOR FEED TUBE GOVERNOR PRESSURE TUBE...

  • Page 148: Installation Of Governor, Modulator, And Torque Converter

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS (2) Position the oil pan on the transmission 7–11. INSTALLATION OF GOVERNOR, housing. MODULATOR, AND TORQUE CONVERTER (3) Refer to Paragraph 3–10b for oil pan in- stallation and torque requirements. Governor SCREW (1) Install the governor cover gasket onto the transmission housing, using oil-soluble grease to re- tain it (Figure 7–36).

  • Page 149: Torque Converter Assembly

    Install the vacuum modulator. CAUTION: (3) Rotate the vacuum modulator until the Allison Transmission Division GM recommends hose nipple faces ten degrees downward (toward bottom only genuine Allison torque converters for use of transmission) and directly forward (Figure 7–38).

  • Page 150: Removal Of Transmission From Overhaul Stand And Installation Of External Components

    AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS 7–12. REMOVAL OF TRANSMISSION (2) Put one gasket 16, separator plate 17, and a second gasket 16 in place on retarder control valve FROM OVERHAUL STAND AND assembly 18. INSTALLATION OF EXTERNAL COMPONENTS (3) Put transfer plate assembly 6 in place on gasket 24 and carefully install four ⁄...

  • Page 151: Checking And Adjusting

    (2) Use the proper shims or gaskets to estab- lish satisfactory gear backlash 0.006–0.029 inch New Installation (0.15–0.73 mm) or as specified by the PTO manufac- turer. (1) Contact Allison Transmission Division of General Motors for approval of planned installation, Determining Turbine-Driven or for recommendations. PTO Backlash...
  • Page 152 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS TRANSMISSION BASE PLATE MAIN CASE GAUGE PIN MEASUREMENT PTO PAD HOLD-DOWN BOLT PTO DRIVE J 34814 GEAR MEASUREMENT CORRECTION 0.011–0.046 inch Correct Height One 0.030 inch Gasket (0.27–1.16 mm) (One 0.76 mm Gasket) 0.047–0.070 inch Correct Height Two 0.030 inch Gaskets (1.19–1.78 mm)

  • Page 153: Section 8. Wear Limits And

    Section 8 – WEAR LIMITS AND SPRING DATA 8–1. WEAR LIMIT DATA 8–2. SPRING DATA (1) Springs must be clean to permit effective inspection. Replace springs if there are signs of over- NOTE: heating, wear due to rubbing adjacent parts, or perma- For detailed inspection criteria, refer to SA1948, nent set.
  • Page 154 AT 500, AT 1500 SERIES AUTOMATIC TRANSMISSIONS Table 8–1. Wear Limits (Cont’d) Wear Limit Illustration Description inch (mm) Foldout 8 FORWARD CLUTCH AND TURBINE SHAFT (cont’d) 27, 28 External-tanged clutch plate Min thickness No visible wear or scoring permitted. Max cone 0.004 0.10 Internal-splined clutch plate —...
  • Page 155 WEAR LIMITS AND SPRING DATA Table 8–1. Wear Limits (Cont’d) Wear Limit Illustration Description inch (mm) Foldout 10,A PLANETARY GEAR UNIT (cont’d) Transmission main shaft — max clearance in bushing 2 0.0045 0.114 Front planetary carrier bushing Max clearance on sun gear 19 0.005 0.12 Output shaft bushing —...
  • Page 156 Table 8–2. Spring Data Spring Free Color Wire dia Length Length Under Load Foldout Spring Part No. Code Coils in. (mm) in. (mm) in. (mm) in. (mm) lb (N) Stator 6774966 No color code Convoluted Spring 0.64 0.30 0.15–0.33 (16.3) (7.6) (0.7–1.5) Main pressure...
  • Page 157 Table 8–2. Spring Data (Cont’d) Spring Free Color Wire dia Length Length Under Load Foldout Spring Part No. Code Coils in. (mm) in. (mm) in. (mm) in. (mm) lb (N) Modulator valve 6833934 Solid white, 0.054 0.49 1.47 0.80 11.90—13.10 orange stripe (1.37) (12.4)
  • Page 158 Table 8–2. Spring Data (Cont’d) Spring Free Color Wire dia Length Length Under Load Foldout Spring Part No. Code Coils in. (mm) in. (mm) in. (mm) in. (mm) lb (N) First clutch trimmer 6833945 Solid light 0.93 2.27 1.94 9.40—11.40 0.092 (2.34) valve (outer)
  • Page 159 Table 8–2. Spring Data (Cont’d) Spring Free Color Wire dia Length Length Under Load Foldout Spring Part No. Code Coils in. (mm) in. (mm) in. (mm) in. (mm) lb (N) Second clutch trimmer 6883300 Solid light 0.082 0.69 1.95 1.10 31.20–37.20 valve (outer) (cont’d) green, white...
  • Page 160 Table 8–2. Spring Data (Cont’d) Spring Free Color Wire dia Length Length Under Load Foldout Spring Part No. Code Coils in. (mm) in. (mm) in. (mm) in. (mm) lb (N) Fourth clutch trimmer 6880045 Orange 0.099 0.94 2.18 1.94 6.20–7.40 valve (outer) (cont’d) (2.51) (23.88)
  • Page 161 Table 8–2. Spring Data (Cont’d) Spring Free Color Wire dia Length Length Under Load Foldout Spring Part No. Code Coils in. (mm) in. (mm) in. (mm) in. (mm) lb (N) 1–2 shift valve 6833935 Solid blue 0.054 0.64 2.17 1.15 8.60–9.10 (1.37) (16.3)
  • Page 162 Table 8–2. Spring Data (Cont’d) Spring Free Color Wire dia Length Length Under Load Foldout Spring Part No. Code Coils in. (mm) in. (mm) in. (mm) in. (mm) lb (N) 2–3 shift valve 6833935 Solid blue 0.054 0.64 2.17 1.15 8.60–9.10 (1.37) (16.3)
  • Page 163 Table 8–2. Spring Data (Cont’d) Spring Free Color Wire dia Length Length Under Load Foldout Spring Part No. Code Coils in. (mm) in. (mm) in. (mm) in. (mm) lb (N) 2–3 shift valve (cont’d) 23012955 Solid green, 13.5 0.062 0.64 2.15 1.15 9.35–9.85...
  • Page 164 Table 8–2. Spring Data (Cont’d) Spring Free Color Wire dia Length Length Under Load Foldout Spring Part No. Code Coils in. (mm) in. (mm) in. (mm) in. (mm) lb (N) 3–4 shift valve (cont’d) 6881061 Solid light blue, 0.054 0.64 2.55 1.15 8.10–8.70...
  • Page 165 Table 8–2. Spring Data (Cont’d) Spring Free Color Wire dia Length Length Under Load Foldout Spring Part No. Code Coils in. (mm) in. (mm) in. (mm) in. (mm) lb (N) Trimmer regulator valve 23018423 Solid lightblue, 12.5 0.041 0.46 1.33 0.86 2.30–2.54 (cont’d)
  • Page 166 AT 500, AT 1500 SERIES AUTOMATIC TRANSMISSIONS NOTES 8–14 Copyright © 1996 General Motors Corp.

  • Page 167: Section 9. Customer Service

    Division (ATD), its distributors, and their dealers. For prompt assistance, please have the following infor- mation available. As an owner of an Allison transmission, you have ser- vice locations throughout the world eager to meet your • Name and location of authorized distributor...

  • Page 168: Service Literature

    Parts Catalog PC1235EN lowing publications. (Check the telephone directory Troubleshooting Manual TS1838EN for the Allison Transmission service outlet nearest Inspection/Analysis GN1948EN you.) Technician’s Guide Automatic Transmission GN2055EN Fluids Technician’s Guide...
  • Page 169 4 – Torque converter stator (AT 543) 5 – Turbine shaft 6 – Oil pump assembly 7 – Front support 8 – Torque converter assembly (AT 540, 542) 9 – Turbine shaft 10 – Oil pump assembly 11 – Front support 12 –...
  • Page 170 OLDOUT V03029 Foldout 1. Model AT 540, 542, 543 Transmission — Cross Section View...
  • Page 171 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS Legend for Foldout 2 1 – Torque converter with lockup clutch assembly (AT 1500 Series) 2 – Turbine shaft 3 – Oil pump assembly 4 – Front support 5 – PTO drive gear 6 – Forward clutch 7 –...
  • Page 172 OLDOUT V01314 Foldout 2. Model AT 545, 1545 Transmission — Cross Section View...
  • Page 173 OLDOUT 1 – Turbine shaft 2 – Oil pump assembly 3 – Front support 4 – Retarder front stator 5 – Retarder rotor 6 – Retarder rear stator 7 – Forward clutch 8 – Third clutch 9 – Fourth clutch 10 –...
  • Page 174 OLDOUT RETARDER-IN RETARDER NOT APPLIED MAIN PRESSURE CONVERTER–IN CONVERTER–OUT RETARDER-OUT LUBRICATION EXHAUST OR SUMP BYPASS TO PRIMARY COOLER FROM PRIMARY COOLER NEUTRAL, FORWARD REGULATOR RETARDER– IN RETARDER–OUT CONVERTER-IN Solenoid De-energized Solenoid De-energized ORIFICE BYPASS ORIFICE Temperature Lube Filter Sender or Retarder Out Pressure Tap Secondary...
  • Page 175 OLDOUT RETARDER-IN 50% RETARDER APPLY MAIN PRESSURE CONVERTER–IN CONVERTER–OUT RETARDER-OUT LUBRICATION EXHAUST OR SUMP BYPASS TO PRIMARY COOLER FROM PRIMARY COOLER NEUTRAL, FORWARD REGULATOR RETARDER– IN RETARDER–OUT CONVERTER-IN Solenoid Energized Solenoid De-energized ORIFICE BYPASS ORIFICE Temperature Lube Filter Sender or Retarder Out Pressure Tap Secondary...
  • Page 176 OLDOUT RETARDER-IN 100% RETARDER APPLY MAIN PRESSURE CONVERTER–IN CONVERTER–OUT RETARDER-OUT LUBRICATION EXHAUST OR SUMP BYPASS TO PRIMARY COOLER FROM PRIMARY COOLER NEUTRAL, FORWARD REGULATOR RETARDER– IN RETARDER–OUT CONVERTER-IN Solenoid Energized Solenoid Energized ORIFICE BYPASS ORIFICE Temperature Lube Filter Sender or Retarder Out Pressure Tap Secondary...
  • Page 177 OLDOUT AT 540 / 542 / 543 / 545 LUBRICATION THIRD CLUTCH PRESSURE SECOND CLUTCH PRESSURE FIRST CLUTCH PRESSURE Forward Fourth Third Second First Oil Cooler Clutch Clutch Clutch Clutch Clutch Pump BYPASS FILTER SUMP ORIFICE FOURTH CLUTCH PRESSURE CONVERTER – OUT Engine CONVERTER –...
  • Page 178 OLDOUT AT 1542 / 1545 LUBRICATION THIRD CLUTCH PRESSURE SECOND CLUTCH PRESSURE FIRST CLUTCH PRESSURE Oil Cooler Forward Fourth Third Second First Clutch Clutch Clutch Clutch Clutch Pump BYPASS FILTER SUMP ORIFICE FOURTH CLUTCH PRESSURE Engine Main Pressure Main Vacuum Regulator Valve Pressure DRIVE–3 PRESSURE...
  • Page 179 1 – Nut, ⁄ -24 (6) A 1 – Torque converter assembly (AT 540, 542, 545, 1542, 1545) 2 – Torque converter assembly (AT 543) 2 – Oil pump and front support assembly 3 – Spacer retainer (6) (earlier models) 3 –...
  • Page 180 OLDOUT V03023 V03024 Foldout 7,A. Torque Converter Assembly (AT 543) — Exploded View Foldout 7,B. Torque Converter and Oil Pump Assemblies — Exploded View...
  • Page 181 OLDOUT 1 – Front stator (models with retarder) 20 – Clutch return spring (16) 2 – Hook-type sealring 21 – Spring retainer 3 – Snapring (earlier models) 22 – Snapring 4 – PTO drive gear (earlier models) 23 – Thrust bearing race 5 –...
  • Page 182 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS Legend for Foldout 9 1 – Snapring (models without retarder) 1 – Snapring 2 – Clutch backplate (models without retarder) 2 – Third clutch backplate 3 – Internal-splined clutch plate (5) (Ident. 4)* 0.416–0.426 inch (10.57–10.82 mm) 4 –...
  • Page 183 OLDOUT V03100 V03025 Foldout 9,A. Fourth Clutch — Exploded View Foldout 9,B. Third Clutch, Second Clutch, and Center Support — Exploded View...
  • Page 184 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS Legend for Foldout 10 37 – Rear planetary carrier 38 – Bronze thrust washer (8) 1 – Sun gear shaft assembly 39 – Steel thrust washer (8) 2 – Bushing (2) (service only) 40 – Pinion (matched set of 4) 3 –...
  • Page 185 OLDOUT 10 11 13 11 V03032 V03026 Foldout 10,A. Planetary Gear Unit — Exploded View Foldout 10,B. First Clutch — Exploded View...
  • Page 186 OLDOUT 1 – Control valve body assembly 44 – Priority valve spring 2 – Separator plate 45 – Priority valve 3 – Bolt, ⁄ -20 x 1 ⁄ (3) A 46 – Hold regulator valve 4 – Adjusting ring (earlier models) 47 –...
  • Page 187 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS Legend for Foldout 12 19 – Filter kit 20 – Sealring 1 – Gasket 21 – Filter assembly 2 – Power takeoff cover 22 – Pan gasket 3 – Bolt, ⁄ -16 x ⁄ (6) A 23 –...
  • Page 188 OLDOUT AT 1500 SERIES 24 25 30 29 V01315 V03028 Foldout 12,B. Oil Pan, Filter, Governor, and Speedometer Drives — Exploded View Foldout 12,A. Transmission Housing, Governor, and Vacuum Modulator — Exploded View...
  • Page 189 AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS Legend for Foldout 13 1 – Gasket 2 – Jumper tube (2) 3 – Complete retarder control assembly 4 – Bolt, ⁄ -20 x 1 ⁄ inch (4) A 5 – Flat washer, ⁄ inch (4) 6 –...
  • Page 190 OLDOUT V03027 Foldout 13. Retarder Control Components...

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