Chapter 10 Manual Transaxle Construction and Operation 209
Copyright by Goodheart-Willcox Co., Inc.
Power in
from engine
Power out
to left
drive wheel
Power out
to right
drive wheel
Splines for clutch
friction disc
Input shaft
Front of car
Output
shaft
Synchronizers
Pinion gear
Differential
assembly
Ring gear
Power in
from engine
Power out to
left drive wheel
Power out to
right drive wheel
Differential assembly
Hypoid ring and
pinion gears
Output shaft
Synchronizers
Clutch
shaft
Drive chain
Input shaft
Countershaft
or cluster
gear shaft
Front of car
Figure 10-4. With the transverse engine, the crankshaft and
input shaft centerlines are in alignment. Also, the crankshaft and
drive axles are oriented in the same direction so diverting power
flow by 90° in the differential is not necessary.
Figure 10-5. With the longitudinal engine, the crankshaft and
input shaft have different centerlines. The drive chain transfers
power from the clutch. A hypoid ring and pinion diverts power
flow at the differential assembly.
Manual transaxle input shaft
The manual transaxle input shaft receives power from
the engine through the clutch. On transaxles used with
transverse engines, the input shaft is a single shaft that is
splined to the clutch friction disc. It extends from the clutch
disc into the transaxle transmission, Figure 10-4. On trans-
axles used with longitudinal engines, the input shaft may
be connected to the clutch through an additional shaft and
a drive chain or drive gears. This is shown in Figure 10-5.
The engine turns the input shaft whenever the clutch is
engaged.
The transaxle input shaft holds gears and synchron-
izers, which are mounted on the shaft in the same manner
as on a rear-wheel drive manual transmission. Excessive
shaft movement is prevented by front and rear bearings and
by thrust washers. The input shaft is sometimes referred to
as the mainshaft or the input cluster gear.
Manual transaxle output shaft
The manual transaxle output shaft contains gears that
mate with the input shaft. This rotating shaft, which holds
output gears and synchronizers, delivers power to the trans-
axle differential. The output shaft is sometimes referred to as
the mainshaft, the countershaft, or the pinion shaft.
Note that some transaxle designs have an output shaft
and a separate countershaft. This arrangement is usually
seen in transaxles used with longitudinal engines. Such
output shafts use a hypoid drive pinion gear to engage the
ring gear in the differential portion of the transaxle.
Reverse idler shaft
Some transaxles have a reverse idler shaft. This is a
short shaft that supports the reverse idler gear, which is an
additional gear used to reverse output shaft direction so the
vehicle can back up. The reverse idler shaft is normally
stationary and mounts in the case.
Manual Transaxle Transmission Gears
The gears of the transmission portion of the manual
transaxle are similar to the gears of a rear-wheel drive
manual transmission. Spur gears or, more often, helical
gears are mounted on the transaxle transmission shafts.
Some gears are cut directly onto the shaft, while others are
splined to the transmission shaft. Some gears rotate on the
shaft, riding on a bushing or on needle bearings placed
between the gear and the shaft.
The gears of the transaxle transmission are used to
transmit power and to provide different gear ratios, as well
as reverse. Transaxle gears, like rear-wheel drive trans-
mission gears, are made of machined high-strength steel.