The 42LE (Fig. 1) is a four-speed transaxle that is
a conventional hydraulic/mechanical assembly with
an integral differential, and is controlled with adap-
tive electronic controls and monitors. The hydraulic
system of the transaxle consists of the transaxle
fluid, fluid passages, hydraulic valves, and various
line pressure control components. An input clutch
assembly which houses the underdrive, overdrive,
and reverse clutches is used. It also utilizes separate
holding clutches: 2nd/4th gear and Low/Reverse. The
primary mechanical components of the transaxle con-
sist of the following:
• Three multiple disc input clutches
• Two multiple disc holding clutches
• Four hydraulic accumulators
• Two planetary gear sets
• Hydraulic oil pump
• Valve body
• Solenoid/Pressure switch assembly
• Integral differential assembly
Control of the transaxle is accomplished by fully
adaptive electronics. Optimum shift scheduling is
accomplished through continuous real-time sensor
feedback information provided to the Transmission
Control Module (TCM).
The TCM is the heart of the electronic control sys-
tem and relies on information from various direct
and indirect inputs (sensors, switches, etc.) to deter-
mine driver demand and vehicle operating condi-
tions. With this information, the TCM can calculate
and perform timely and quality shifts through vari-
ous output or control devices (solenoid pack, trans-
mission control relay, etc.).
The TCM also performs certain self-diagnostic
functions and provides comprehensive information
(sensor data, DTC’s, etc.) which is helpful in proper
diagnosis and repair. This information can be viewed
with the DRB scan tool.
TRANSAXLE IDENTIFICATION
The 42LE transaxle identification code is a series
of digits printed on a bar-code label that is fixed to
the transaxle case as shown in (Fig. 2).
For example, the identification code K 821 1125
1316 can be broken down as follows:
• K = Kokomo Transmission Plant
• 821 = Last three digits of the transaxle part
number
• 1125 = Build date
• 1316 = Build sequence number
If the tag is not legible or missing, the “PK” num-
ber, which is stamped into the transaxle case, can be
referred to for identification. This number differs
slightly in that it contains the entire transaxle part
number, rather than the last three digits.
OPERATION
Transmission output is directed to an integral dif-
ferential by a transfer gear system in the following
input-to-output ratios:
First .............................. 2.84 : 1
Second ............................. 1.57 : 1
Third .............................. 1.00 : 1
Overdrive .......................... 0.69 : 1
Reverse ............................ 2.21 : 1
1 – DIFFERENTIAL
2 – TRANSFER SHAFT
3 – TRANSFER GEAR
4 – FRONT PLANETARY CARRIER
5 – REAR PLANETARY CARRIER
6 – OUTPUT SHAFT
7 – OUTPUT GEAR
8 – OUTPUT SPEED SENSOR
9 – LOW/REVERSE CLUTCH
10 – 2/4 CLUTCH
11 – REVERSE CLUTCH
12 – OVERDRIVE CLUTCH
13 – UNDERDRIVE CLUTCH
14 – INPUT SPEED SENSOR
15 – CONVERTER CLUTCH
16 – OIL PUMP
17 – INPUT SHAFT
18 – TORQUE CONVERTER
Fig. 2 Transaxle Identification Label
1 – INPUT SPEED SENSOR
2 – OUTPUT SPEED SENSOR
3 – IDENTIFICATION TAG
LH 42LE TRANSAXLE 21 - 3
DESCRIPTION AND OPERATION (Continued)
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