Copyright by Goodheart-Willcox Co., Inc.
380 Automatic Transmissions and Transaxles
Air pressure will
pop out
piston and cover
Case
Air hose
Air gun
Servo
release
port
Figure 15-25. Some servos must be removed with air pressure,
as shown in this illustration. Always make sure that the servo
does not fly out of the case when air pressure is applied.
(Chrysler)
Replace
servo seals
Check pistons
for wear,
scoring, etc.
Figure 15-26. Most servos can be serviced by replacing their
seals. The servo should be checked for any signs of wear.
Return servo pistons and springs to their original positions.
Sliding caliper
Spring
free
length
Retainer
plus spring
measurement
Measure
used springs
Spring
retainer
Figure 15-27. Servo return spring length can be measured with
a sliding caliper. Undersized springs should be replaced.
(Chrysler)
Note: The replacement of some sealing
devices, such as the front pump seal, O-ring,
and pump-to-case gasket, requires that the
transmission or transaxle be removed from the
vehicle. Replacement of tailshaft housing seals and
axle shaft seals requires that the drive shaft or
CV axle be removed.
Accumulators visually resemble servos and should be
checked and repaired in a similar manner. Access the accu-
mulator by removing the accumulator cover, if one is used,
or by removing the valve body. Many accumulators are
installed under the valve body or are part of the valve body.
Valve body removal was covered earlier in this chapter.
Withdraw the accumulator piston and spring(s). Some
accumulators also have a removable pin, which will come
out with the piston. Inspect all parts for wear, nicks, or
burrs. Carefully inspect the pin and the internal accumula-
tor bore where it rides on the pin. Wear in this area is com-
mon, especially on plastic or aluminum accumulators that
are used during more than one shift. You may find a broken
accumulator piston, especially on an accumulator that is
designed to cushion the application of the forward clutch.
Also check the accumulator bore for scoring. Replace any
defective parts. Always replace the accumulator seals and
seal rings.
Replacing Leaking Seals, O-Rings,
and Gaskets
Once a leaking seal, O-ring, or gasket has been locat-
ed, it can be replaced by disassembling the mating parts
and replacing the leaking component. The following gen-
eral procedures cover the removal and installation
of seals, O-rings, and gaskets that commonly leak. For
additional gasket and seal replacement information, as well
as information on adhesive compounds, RTV sealant, and
gasket-making compounds, refer to Chapter 5.