Dodge D150 1990 Service Manual page 967

21-116 AUTOMATIC TRANSMISSION
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OVERDRIVE UNIT REMOVAL
The overdrive removal a n d i n s t a l l a t i o n procedures
i n t h i s section apply to the overdrive u n i t only. I f t h e
complete transmission assembly must be removed for
service, refer t o the procedures i n the three speed
transmission section.
(1) Shift t h e transmission i n t o Park.
(2) Raise t h e vehicle.
(3) Remove the transmission o i l pan and gasket
and d r a i n t h e fluid. T h e n r e i n s t a l l the o i l pan plus a
new gasket.
(4) I f the malfunction involved an overdrive clutch
or governor problem, remove only the overdrive u n i t .
However, i f the failure generated m e t a l particles, or
i f the fluid is contaminated w i t h friction m a t e r i a l , re-
move t h e e n t i r e transmission.
(5) M a r k propeller shaft universal j o i n t and axle
p i n i o n yoke for a l i g n m e n t reference (Fig. 1).
Fig. 1 Mark Propeller Shaft And Yoke For Alignment
Reference
(6) Disconnect and remove the propeller shaft, or
shafts on four wheel drive models.
(7) O n four wheel drive models, remove the trans-
fer case f r o m the overdrive u n i t .
(8) Support the transmission w i t h a transmission
jack.
(9) Remove t h e crossmember. M a r k position o f
crossmember for reassembly.
(10) Remove the distance sensor and speedometer
adapter.
(11) Remove the bolts a t t a c h i n g the overdrive u n i t
to the t r a n s m i s s i o n (Fig. 2).
CAUTION: Support the overdrive unit during re-
moval. Do not allow the front section intermediate
shaft to support the entire weight of the overdrive
unit.
(12) C a r e f u l l y slide the overdrive u n i t off the i n t e r -
mediate shaft. Retain t h e bearing a n d select fit
Fig. 2 Removing/Installing Overdrive Unit Attaching
Bolts
spacer t h a t m a y r e m a i n on the overdrive piston, rear
of the t r a n s m i s s i o n case, s l i d i n g h u b , or i n t e r m e d i a t e
shaft.
(13) Place several clean shop towels o n the w o r k -
bench.
(14) T i l t t h e overdrive u n i t t o d r a i n a n y fluid r e -
m a i n i n g i n t h e case. E x a m i n e the fluid for clutch
m a t e r i a l or m e t a l fragments. I f the fluid contains
these items, a n overhaul w i l l be necessary.
OVERDRIVE VALVE BODY SERVICE
GENERAL SERVICE INFORMATION
The upper p a r t o f the overdrive valve body is sim-
i l a r t o t h e three speed automatic transmission valve
body (Fig. 3). I t contains the t h r o t t l e valves, gover-
nor plugs, pressure regulators, 1-2 shift valves, pres-
sure adjustment components and the m a n u a l valve
and lever. Refer to the Loadflite transmission section
for service procedures.
The lower section o f the overdrive valve body (Fig.
3) contains the f o u r t h gear shift components. These
include t h e 3-4 shift valve, 3-4 accumulator, 3-4 t i m -
i n g valve, lockup and t i m i n g valves, 3-4 shuttle and
t i m i n g valves and the dual overdrive/lockup solenoid
assembly (Fig. 3).
VALVE BODY REMOVAL/INSTALLATION
Removal a n d i n s t a l l a t i o n procedures f o r the over-
drive valve body are the same as for t h e three speed
valve body. Refer t o t h e procedures i n t h e three
speed t r a n s m i s s i o n section.
VALVE BODY OVERHAUL AND ADJUSTMENT
The overdrive valve body overhaul procedures v a r y
f r o m t h e three speed procedures only i n regard t o
lower h o u s i n g components (Fig. 4). C l e a n i n g and i n -
spection methods are the same except for the d u a l so-
lenoid assembly a n d solenoid connector. These