be removed. The gearsets, holding members, and output
shaft can usually be removed through the front of the case.
It may be necessary to remove the parking gear before
removing the output shaft.
Once the mechanical components mentioned are
removed, any internally mounted accessories can be
removed. Examples of these parts include some servos,
accumulators, clutch apply pistons (usually used at rear of
case), and governors. If these parts are not mounted inside
the case—for example, if they mount inside the oil pan—
they will be removed with the other external components.
Note that many servos and accumulators are under
strong spring pressure. Always consult the service manual
before removing any retaining rings or bolts. It may be
easier to leave the servos and accumulators installed in the
case until it is time to inspect them and replace their seals.
If the transmission is filled with sludge and debris,
however, these parts should be removed at this time for a
thorough cleaning.
Automatic Transmission and Transaxle
Parts Cleaning
All automatic transmission or transaxle parts must be
cleaned thoroughly. This is very important because small
dirt particles or varnish formation can cause a passageway
to plug up, a valve to stick, or a seal to leak.
Carefully scrape all old gasket material from the case,
oil pan, and other parts. Pay attention to the gaskets on
hydraulic control assemblies, such as the front pump, the
valve body, and the spacer plates.
Clean all metal parts, including the case, with a safe
solvent. It may be necessary to soak parts overnight. Do
not clean clutch friction linings or seals with solvent. To
avoid having a confusing pile of parts, always remember to
work on one subassembly at a time while cleaning.
Dry the cleaned parts with compressed air (if possible) or
allow them to air dry. Do not use rags or shop towels to dry
the parts, because they will leave lint on the parts. The lint
left behind can cause valves to stick. It is better to leave
slight deposits of solvent on the parts than to dry them with
rags or shop towels. Once cleaned, cover the disassembled
parts with a clean lint-free cloth if they are to sit out overnight.
Drain the torque converter. If there is a drain plug,
remove it and set the converter upright with the drain at
the lowest point. On converters without a drain plug, lay
the center opening face down. This will allow most of the
old transmission fluid to drain from the converter.
If the internal parts were very dirty or heavily coated
with varnish, the torque converter will be full of dirt and
varnish. A torque converter that is filled with dirt or metal
particles can be cleaned with a converter flusher.
Converter flushers were introduced in Chapter 3. A heavily
varnished converter, however, is difficult to clean and is
often replaced.
If there is evidence of fluid contamination, the oil
cooler and cooler lines must be flushed out. One way to
do this is to use an oil cooler and line flusher and follow
up with a blast of compressed air directed into one of the
cooling lines. Have a drain pan available to catch solvent
flowing from the other line. Do not apply full air pressure
to the cooling lines, as this could rupture the oil cooler. A
badly contaminated oil cooler cannot be completely
cleaned. Therefore, the radiator should be replaced or the
cooler should be bypassed by installing an external oil
cooler when a badly contaminated unit is encountered.
Parts Inspection and Repair
Once the transmission or transaxle is disassembled and
cleaned, the parts can be inspected, replacement parts can
be ordered, and subassemblies can be rebuilt. In this
section, parts inspection and repair will be covered when
describing the service of each subassembly. During an
actual rebuild, internal parts will be inspected during and
immediately after the unit is taken apart and cleaned. You
should inspect transmission or transaxle parts one
subassembly at a time. In this way, you can order replace-
ment parts right away, eliminating time lost waiting for parts.
Chapter 17 Rebuilding Automatic Transmissions and Transaxles 405
Center
support
Center support
retaining ring
Bell
housing
Figure 17-8. Many modern transmissions and transaxles have
a center support. The support shown here is held in place with
a retaining ring, which must be removed before removing the
rear planetary gearset and holding members, as well as the
output shaft. (Ford)
Warning: Never clean parts with gasoline or
other flammable solvents. A fire could
result!