mine the amount of endplay, Figure 17-13. Planetary
gearsets often contain bushings or needle bearings that
wear out. These should be carefully checked, as well. Any
parts that are worn or damaged should be replaced.
Visually inspect needle bearings and Torrington (flat)
bearings and try to rotate them by hand. If you feel any
roughness when turning a clean bearing or a gear that rides
on a bearing, replace the bearing. If you suspect that a
bearing inside a gearset is worn, take the time to disas-
semble the gearset and check the bearing.
Bushings can be checked visually. If a bushing shows signs
of wear or scoring, replace it. A bushing that looks good can
be excessively worn. Check bushings for wear by inserting
the mating shaft or race into the bushing and trying to rock
the shaft or race back and forth. If the shaft or race rocks
excessively, the bushing is loose and should be replaced.
Clutch Pack Service
One of the most important parts of automatic trans-
mission overhaul is the proper checking and rebuilding of
the clutch packs. These operations are discussed in the
following sections.
Clutch Pack Disassembly and Inspection
To begin disassembly, use a screwdriver to remove the
snap ring that holds the plates and friction discs in the
clutch drum. See Figure 17-14. Then, remove the plates
and discs. Unless they are excessively worn, the discs and
plates will fall out when the drum is turned over. Keep all
the steel plates together, noting if there are any reaction
plates (thicker steel plates) at the top and bottom of the
stack, Figure 17-15. Never interchange one set of clutch
pack parts with another.
Inspect the steel plates. Look for discoloration, which
is caused by overheating and is often a sign of a badly
slipping clutch pack. A common sign of overheating is
leopard spotting, Figure 17-16. Look for worn or scored
Chapter 17 Rebuilding Automatic Transmissions and Transaxles 407
Carrier
Feeler
gauge
Planet
gear
Clearance
Figure 17-13. The planet gears and planet carrier can be
checked for wear with a feeler gauge, as shown here.
Disassembly is not required to make this check. (Nissan)
Fourth clutch
snap ring
Tool
Remove
discs
and plates
Figure 17-14. The clutch packs should be disassembled to
check for burned friction discs and other problems. Most clutch
packs are held together with a large snap ring, as shown here.
(General Motors)
Direct
clutch pack
Keep parts
together and
in sequence
Sliding hub
Figure 17-15. Inspect the clutch plates for wear, burning,
scoring, and other damage. Also, check the drum, bushings,
hub splines, and thrust washers. Replace parts that show signs
of wear or damage. (DaimlerChrysler)
Figure 17-16. Steel plates showing leopard spots are often
found when the transmission or transaxle is disassembled.
Leopard spots are named for their resemblance to a leopard’s
coat and are a sign of severe clutch overheating. The dark
spots are areas where the metal has become so overheated
that it has lost its strength and resistance to wear.