Dodge RAM TRUCK 1500 1995 Service Manual page 1389

21 - 106 42RH/46RH/47RH TRANSMISSION DIAGNOSIS AND TESTIIS — — — _ — _ E H
page
Air Testing Transmission Clutch and Band
Operation 112
Analyzing the Road Test 108
Causes of Burned Fluid . 107
Checking Fluid Level and Condition . 106
Converter Housing Fluid Leak Diagnosis . . . . . . . 112
Converter Stall Test 111
Diagnosis Charts 116
Effects of Incorrect Fluid Level 107
Fluid Contamination . . . . . . . . . . . . . . . . . . . . . . 107
GENERAL INFORMATION
Automatic transmission problems can be a result of
poor engine performance, Incorrect fluid level, Incor­
rect linkage adjustment, band or hydraulic control
pressure adjustments, hydraulic system malfunctions
or electrical/mechanical component malfunctions.
Begin diagnosis by checking the easily accessible
items such as: fluid level and condition, linkage ad­
justments and electrical connections on 4-speed mod­
els. A road test will determine if further diagnosis is
necessary.
Procedures outlined in this section should be per­
formed in the following sequence to realize the most
accurate results:
• Preliminary diagnosis
• Fluid Level and condition
• Leak tests (if fluid level is low)
• Linkage Adjustments
• Overdrive off switch test
• Road test
• Stall test
• Hydraulic pressure test
© Air pressure tests
• Analyze test results and consult diagnosis charts
PRELIMINARY DIAGNOSIS
Two basic procedures are required. One procedure
for vehicles that are driveable and an alternate pro­
cedure for disabled vehicles (will not back up or move
forward).
VEHICLE IS DRIVEABLE
(1) Check fluid level and condition.
(2) Adjust throttle valve cable and gearshift link­
age if complaint was based on delayed, erratic, or
harsh shifts.
(3) Road test and note how transmission upshifts,
downshifts and engages.
page
Gearshift Linkage . . . . . . . . . . . . . . . . . . . . . . . . 108
General Information 106
Hydraulic Pressure Test 109
Overdrive Fourth Gear Electrical Controls . . . . . . 108
Preliminary Diagnosis . . . . . . . . . . . . . . . . . . . . . 106
Road Testing 108
Stall Test Analysis 112
Throttle Valve Cable Adjustment 108
(4) Perform stall test if complaint is based on slug­
gish acceleration or if abnormal throttle opening is
needed to maintain normal speeds with a properly
tuned engine.
(5) Perform hydraulic pressure test if shift prob­
lems were noted during road test.
(6) Perform air pressure test to check clutch-band
operation.
VEHICLE IS DISABLED
(1) Check fluid level and condition.
(2) Check for broken, disconnected gearshift and
throttle linkage.
(3) Check for cracked, leaking cooler lines, or loose,
missing pressure port plugs.
(4) Raise vehicle, start engine, shift transmission
into gear and note following:
(a) If propeller shaft turns but wheels do not,
problem is with differential or axle shafts.
(b) If propeller shaft does not turn and transmis­
sion is
noisy, stop engine. Remove oil pan, and check for
debris. If pan is clear, remove transmission and
check for damaged drive plate, converter, oil pump
or input shaft.
(c) If propeller shaft does not turn and transmis­
sion is not noisy, perform hydraulic pressure test to
determine if problem is a hydraulic or mechanical.
CHECKING FLUID LEVEL AND CONDITION
Transmission fluid level should be checked a mini­
mum of six times per year under normal operation. If
the vehicle is used for trailer towing or similar heavy
load hauling, check fluid level and condition at
least once a week.
Fluid level is checked with the engine running at
curb idle speed, brakes applied, transmission in Neu­
tral, and the transmission fluid at normal operating
temperature (hot).
(1) Transmission fluid must be at normal operating
temperature for accurate fluid level check. Drive ve-
4 2 R H / 4 6 R H / 4 7 R H
TRANSMISSION DIAGNOSIS AND YESTifl©
INDEI