Servo and Accumulator Service
Band servos and accumulators should always be disas-
sembled to replace seals, inspect for worn hard parts, and
remove accumulated sludge. The inspection and repair of
servos and accumulators was covered in Chapter 15.
Overrunning Clutch Service
All overrunning clutches in the transmission or
transaxle should be checked to ensure that they turn freely
in the direction they should and lock up in the other direc-
tion. See Figure 17-30. Any overrunning clutch that turns
in both directions must be replaced. Also, any clutch
showing signs of wear should be replaced. Make sure the
new clutch turns in the proper direction when installed.
CVT Belt and Pulley Service
CVT belt and pulley arrangements are similar, but
each one has specific repair processes. Always consult the
proper service information before beginning disassembly.
Belt removal on most CVTs requires a special tool that is a
combination of a holding fixture and a clamping tool. The
CVT assembly is placed in the holding fixture. A U-shaped
clamping ring is positioned around the sliding portion of
the drive pulley and locked to levers on the tool. When the
levers are depressed, force is applied to the clamping ring,
driving the bottom portion of the pulley downward to the
fully open position. With both pulleys in the fully open
position, the belt can be easily removed.
Once the belt has been removed, check the belt and
pulley sheaves for wear and damage. Replace any defec-
tive parts. To reinstall the belt, place it in position in the
pulleys and lubricate all parts with the correct type of fluid.
Then slowly release the levers on the special tool. Finally,
inspect the belt to ensure that it is properly reinstalled.
Oil Pump Service
The front oil pump must be disassembled to check it
properly. Most pumps are held together by bolts. Some
pumps contain the pressure regulator valve and other valves.
A few pumps contain a clutch apply piston assembly.
Once the pump has been taken apart, check it for wear
in areas where the gears, rotors, or vanes ride against the
stationary pump body. Badly worn, scored, or pitted pumps
can usually be detected visually, Figure 17-31. Scratch the
suspect area with a fingernail to confirm the presence of wear
or scoring. In addition, the condition of the pump can be
assessed with the help of feeler gauges, Figure 17-32.
Since the oil pump is designed to provide much more
pressure than needed, a slightly worn pump can be reused.
When reusing an old pump, make sure the wear is slight
and the parts are reinstalled in their original positions. The
pump’s internal elements usually have factory marks to
help ensure proper installation.
Always replace the front pump seal, no matter how
good it appears. Replace the pump bushing, if needed. The
pump bushing is critical since a worn bushing can cause
the new seal to leak. Proper removal and installation tools
should always be used, Figure 17-33. Stake the bushing in
place to prevent it from moving. Some transmissions and
transaxles have high pump bushing failure rates. Aftermarket
kits have been developed to solve this problem, Figure 17-34.
412 Automatic Transmissions and Transaxles
Figure 17-30. Testing a one-way clutch. A—Clutch turns easily in
one direction. B—Clutch does not turn at all in opposite direction.
Scored
area
Figure 17-31. This pump body is severely scored at the pump
gear-riding surface. A pump body in this condition should not be
reused. When the pump body shows this much wear, check the
pump cover for similar wear.
A
B