On Vehicle Service; Parts Cleaning, Inspection And Replacement - GMC G Service Manual

TORQUE CONVERTER
EVALUATION
TORQUE CONVERTER STATOR
The torque converter stator roller clutch can have one of
two different malfunctions:
1. Stator assembly freewheels in both directions.
2. Stator assembly remains locked up at all times.
Condition 1 — Poor Acceleration Low Speed
The vehicle tends to have poor acceleration from a
standstill. At speeds above 30-35 MPH (50-55 KPH), the
vehicle may act normal. If poor acceleration is noted, first
determine that the exhaust system is not blocked, the
engine timing is correct and the transmission is in first (1st)
gear when starting from a standstill.
If the engine freely accelerates to high r.p.m. in "Neutral"
(N), it can be assumed that the engine and exhaust system
are normal. Checking for poor performance in "Drive" (D)
and "Reverse" (R) will help determine if the stator is free­
wheeling at all times.
Condition 2 — Poor Acceleration High Speed
In this condition, engine r.p.m. and vehicle speed is lim­
ited or restricted at high speeds. Performance when
PARTS CLEANING, INSPECTION
AND REPLACEMENT
1. Use appropriate safety equipment such as:
• Safety glasses.
• Safety shoes.
• Gloves.
2. Keep work area and tools clean.
3. Clean the transmission exterior before removing
parts.
4. Do not use wipe cloths or rags.
5. Do not use solvents on:
• Rubber seals.
• Plastic/Teflon® thrust washers.
6. Blow out all passages with compressed air.
7. Clean out small passages with fine wire.
8. Handle parts carefully to prevent damage.
9. Lubricate all internal parts with transmission fluid dur­
ing assembly.
10. When installing screws, bolts or studs into aluminum
always dip the threads in transmission fluid.
11. Always use a torque wrench for proper torque.
12. Recondition damaged or stripped aluminum threads
with thread inserts.
ON-VEHICLE SERVICE
TRANSMISSION 7A-63
accelerating from a standstill is normal. Engine may over­
heat. Visual examination of the converter may reveal a blue
color from overheating.
If the converter has been removed, the stator roller
clutch can be checked by inserting a finger into the splined
inner race of the roller clutch and trying to turn the race in
both directions. The inner race should turn freely clockwise,
but not turn or be very difficult to turn counterclockwise.
The Converter Should Be Replaced If:
• External leaks, such as at the hub weld area, are
present.
• The converter has an imbalance which cannot be
corrected.
• The converter is contaminated with engine coolant
containing antifreeze.
The Converter Should Not Be Replaced If:
• The oil has an odor, is discolored and there is no
evidence of metal or clutch facing particles.
• The threads of one or more of the three converter bolt
holes are damaged.
• Correct with a thread insert.
13. Replace all gaskets and seals.
• Do not use gasket cement or sealers.
14. Replace Teflon® and rubber lip seals only when nec­
essary and install them using the appropriate seal
protector.
I P j Inspect
1. Manual linkage for:
• Wear at pivoting points.
• Bent or broken links and rods.
2. All seals, gasket and mating surfaces for:
• Nicks.
• Cuts.
• Damage.
3. Snap rings for:
• Expansion or compression.
• Distortion.
• Nicks.
• Proper ring to groove fit.
4. Bearings and thrust surfaces for:
• Wear.
• Scoring.
• Pitting.