Diagnosis And Testing - Hydraulic Pressure Tests - Chrysler Vehicle User Manual

21 - 78 AUTOMATIC TRANSMISSION - 42RLE
AUTOMATIC TRANSMISSION - 42RLE (Continued)
The process of elimination can be used to detect any
unit which slips and to confirm proper operation of
good units. Road test analysis can diagnose slipping
units, but the cause of the malfunction cannot be
determined. Practically any condition can be caused by
leaking hydraulic circuits or sticking valves.
DIAGNOSIS AND TESTING - HYDRAULIC
PRESSURE TESTS
Pressure testing is a very important step in the
diagnostic procedure. These tests usually reveal the
cause of most transmission problems.
Before performing pressure tests, be certain that
fluid level and condition, and shift cable adjustments
have been checked and approved. Fluid must be at
operating temperature (150 to 200 degrees F.).
Install an engine tachometer, raise vehicle on hoist
which allows the wheels to turn, and position
tachometer so it can be read.
Using special adapters L-4559, attach 300 psi
gauge(s) C-3293SP to the port(s) required for test
being conducted.
Test port locations are shown in (Fig. 8).
Fig. 8 Pressure Taps
1 - TORQUE CONVERTER CLUTCH OFF
2 - REVERSE
3 - LOW/REVERSE
4 - 2/4
5 - UNDERDRIVE
6 - TORQUE CONVERTER CLUTCH ON
7 - OVERDRIVE
TEST ONE-SELECTOR IN L (1st Gear)
NOTE: This test checks pump output, pressure reg-
ulation and condition of the low/reverse clutch
hydraulic circuit and shift schedule.
(1) Attach pressure gauge to the low/reverse clutch
tap.
(2) Move selector lever to the L position.
(3) Allow vehicle wheels to turn and increase throttle
opening to achieve an indicated vehicle speed to 20 mph.
(4) Low/reverse clutch pressure should read 115 to
145 psi.
TEST TWO-SELECTOR IN DRIVE (Second Gear)
NOTE: This test checks the underdrive clutch
hydraulic circuit as well as the shift schedule.
(1) Attach gauge to the underdrive clutch tap.
(2) Move selector lever to the 3 position.
(3) Allow vehicle wheels to turn and increase
throttle opening to achieve an indicated vehicle speed
of 30 mph.
(4) In second gear the underdrive clutch pressure
should read 110 to 145 psi.
TEST TWO A–SELECTOR IN OD (Fourth Gear)
NOTE: This test checks the underdrive clutch
hydraulic circuit as well as the shift schedule.
(1) Attach gauge to the underdrive clutch tap.
(2) Move selector lever to the OD position.
(3) Allow wheels to rotate freely and increase
throttle opening to achieve an indicated speed of 40
mph.
(4) Underdrive clutch pressure should read below
5 psi. If not, than either the solenoid assembly or
controller is at fault.
TJ