Introduction
Rebuilding, or overhauling, automatic transmissions and
transaxles requires extensive knowledge and careful work
habits. This chapter will outline automatic transmission
and transaxle overhaul procedures. If you have studied the
information in Chapter 3 and in Chapters 8–10, you will be
familiar with the components and tools discussed in this chapter.
This chapter presents general procedures for
rebuilding automatic transmissions and transaxles. Always
refer to the manufacturer’s service manual for specific
information. It will contain accurate instructions for disas-
sembling, cleaning, inspecting, and rebuilding the unit at
hand. Note that certain procedures performed as part of
the rebuilding operation—valve body service, for
example—were covered in Chapter 15.
Although a typical automatic transmission or
transaxle contains many parts, it can be successfully
rebuilt if you follow logical procedures.
Special service tools are sometimes needed when
rebuilding an automatic transmission or transaxle. These
tools can be purchased from the vehicle dealer or ordered
directly from the manufacturer. Refer to Chapter 2 for more
information on special service tools used to service auto-
matic transmissions and transaxles.
Automatic Transmission and
Transaxle Disassembly
Before beginning disassembly of a transmission or
transaxle, clean the outside of the unit thoroughly and
mount the unit in a holding fixture, Figure 17-1. If a
holding fixture is not available, place the assembly on a
clean workbench. The workbench should be constructed
so that transmission fluid can drain into a catch basin.
As you remove the major parts of the transmission or
transaxle, set them aside for further disassembly. Then work
on one subassembly (pump, clutch pack, or servo, for
example) at a time. This will help you keep things straight.
Removing External Components
The first step in disassembly is to remove the torque
converter holding tool and the torque converter from the
transmission or transaxle. Before proceeding, check the
converter housing for dents or obvious leakage, and for
stripped converter attaching bolt holes. Check the converter
crankshaft pilot projection for burrs or damage, and check
the oil pump driving lugs (if used) for wear or burrs.
Then check input and output shaft endplay as shown in
Figure 17-2. Endplay (back-and-forth movement of the shaft)
should be checked before the transmission or transaxle is
disassembled (and again after it is reassembled). Record the
endplay readings for later reference. Excessive endplay
indicates wear of the thrust washers and other parts. This
should be corrected during the rebuilding process.
402 Automatic Transmissions and Transaxles
Note: For transaxle final drive rebuilding
information, refer to Chapter 18.
Transmission
stand or fixture
Automatic
transmission
Figure 17-1. It is much easier to overhaul a transmission or
transaxle if it is placed in a special holding fixture. (Nissan)
Dial
indicator
Adapter
Input
shaft
Oil
pump
Mounting rod
A
Output
shaft
Mounting
rod
Dial indicator
B
Figure 17-2. Always check endplay before disassembling the
transmission.The service manual will contain the endplay spec-
ifications and the procedures for setting up the dial indicators.
A—Checking input shaft endplay. B—Checking output shaft
endplay. (General Motors)