Copyright by Goodheart-Willcox Co., Inc.
214 Manual Drive Trains and Axles
1–2 lock
ball and
spring
Roll pin
Shift rail
3–4 shift fork
Roll pin
No. 1
shift rail
No. 2
shift rail
No. 3
shift rail
No. 1
shift fork
No. 2
shift fork
No. 3
shift fork
Slotted
spring pin
Slotted
spring pin
Reverse
shift fork
Slotted
spring pin
Slotted
spring pin
Interlock
pins
Gear shift
head
Reverse shift
arm
Inner
spring seat
Outer
spring seat
Cover
5th/rev bias
spring
9.0 N·m
(84 lb in.)
screw
Snap ring
Figure 10-18. Detents fit into notches on the shift rails to keep
the shift forks and shift rails in place once the desired gear is
selected. The spring puts pressure on the shaft to keep it in
place. (General Motors)
Figure 10-16. Some transaxle internal shift linkages use
multiple shift rails. Notice the relative positions of the shift rails
and shift forks inside a transaxle case. (Chrysler)
Figure 10-17. An exploded view of a shift rail system. Interlock
pins make it impossible to move more than one rail at a time.
This ensures that only one gear can be engaged during a shift.
(Toyota)
Internal shift linkage
The shift fork is operated inside the transaxle by a
series of levers or more often, by a shifter shaft or shift rails
that slide in holes drilled in the case. See Figure 10-16. The
shift rail system is used on many transaxles and trans-
missions. It consists of a series of rods (shift rails), which
operate the shift forks. The rails move in a straight line. The
shift forks are attached directly to the shift rails.
An exploded view of a shift rail system is shown in
Figure 10-17. This system has four shift forks, which are
used to select the transaxle’s six forward gears and one
reverse gear. Notches seen along the shift rails are for
detents. These spring-loaded devices keep the levers and,
therefore, the fork and synchronizer sleeve in position
when they are not being moved by the driver.
Note that one kind of detent is inside a separate cover,
which is installed in the case with a snap ring, Figure 10-18.
This design serves the same purpose as other detent
systems, but it can be serviced from outside the case.
Manual Transaxle Differential Assembly
The transaxle differential assembly is the part of the
transaxle that allows the front wheels to turn at different
speeds when the vehicle is turning a corner. The action of