IDENTIFICATION
Transaxle identification code is stamped on identification tag located on side of transaxle. (Scheme 1) Transaxle identification code may be required when ordering replacement components.
Scheme 1
DESCRIPTION
The 42LE is an electronically controlled 4-speed transaxle. Transaxle uses hydraulically operated clutches controlled by Transaxle Control Module (TCM). Transaxle consists of 3 multiple-disc input clutches, 2 multiple-disc holding clutches, 4 hydraulic accumulators and 2 planetary gear sets to provide 4 forward speeds and reverse. (Scheme 2)
TCM receives information from various sensors and controls the solenoid assembly through the transaxle control relay. Solenoid assembly consists of 4 solenoids for controlling hydraulic pressure to 4 of the 5 transaxle clutches.
TCM contains an adaptive memory which learns application and release rates of transaxle components for smooth operation. TCM also learns rate at which applied elements build pressure sufficient for a speed change. Adaptive control can adapt to altitude, temperature, engine output, etc.
| CAUTION | If battery is disconnected or voltage supply to TCM is interrupted, TCM must relearn shift characteristics. If TCM, transaxle internal components, solenoid assembly or torque converter are replaced, TCM will have to relearn shift characteristics. Perform shift quality quick-learn procedure. See SHIFT QUALITY QUICK-LEARN PROCEDURE in CHRYSLER 42LE ELECTRONIC CONTROLS article. |
| CAUTION | If TCM is replaced or changed from one vehicle to another, proper procedure must be followed to calibrate TCM for different equipment combinations to provide speedometer operation and correct readings. Failure to perform this procedure will result in no speedometer operation. See PINION FACTOR PROCEDURE in CHRYSLER 42LE ELECTRONIC CONTROLS article. |
OPERATION
- Models Without Autostick When gearshift lever is in "OD" (overdrive) position, transaxle will shift through all 4 speeds with torque converter lock-up in Overdrive. When gearshift lever is in "3" position, transaxle uses only 1st, 2nd and 3rd gears with 2nd-to-3rd gear shift delayed until vehicle speed is at least 40 MPH. When operating with gearshift lever in "3" position, torque converter lock-up occurs in 3rd gear for improved transaxle cooling. If engine coolant temperature becomes excessively warm, torque converter lock-up will occur in 2nd gear. When gearshift lever is in "L" position, engine braking is provided for descending grades.
- Models With Autostick (Intrepid, Prowler & 300M) With gearshift lever in "OD" position, transmission shift schedule is same as non-autostick vehicle. When gearshift lever is moved into "A/S" (autostick) position, transaxle remains in same gear until gearshift lever is moved to left (downshift) or right (upshift). Vehicle can be driven from a complete stop in 1st, 2nd or 3rd gear. Shifting into "OD" position cancels autostick mode and transaxle resumes OD shift schedule. For safety, durability and driveability, some shifts are executed automatically or prevented. See «AUTOSTICK OVERRIDE SHIFT SCHEDULE»(ref-91454-S30688044732001031700000) table.
- All Models TCM contains a self-diagnostic system which stores a DTC if a transaxle problem is present. DTCs can be retrieved to determine the transaxle problem area. For information on electronic transaxle components, see CHRYSLER 42LE ELECTRONIC CONTROLS article.
| Shift Sequence | Condition | ||
|---|---|---|---|
| Automatic Shifts | |||
| 4-3 Coast | 13 MPH | ||
| 3-2 Coast | 9 MPH | ||
| 2-1 Coast | 5 MPH | ||
| 1-2 Upshift | |||
| 2.7L & 3.2L | 6300 RPM | ||
| 3.5L | 6600 RPM | ||
| 2-3 | |||
| 2.7L & 3.2L | 6300 RPM | ||
| 3.5L | 6600 RPM | ||
| 4-3 Kickdown | 13-47 MPH | ||
| Overridden Manual Shifts | |||
| 3-4 | Less Than 15 MPH | ||
| 3-2 | (1) | ||
| 2-1 | (2) | ||
| (1) 74 MPH or more with closed throttle, or 70 MPH with any other throttle position. (2) 41 MPH or more with closed throttle, or 38 MPH with any other throttle position. | |||
| (1) | 74 MPH or more with closed throttle, or 70 MPH with any other throttle position. |
| (2) | 41 MPH or more with closed throttle, or 38 MPH with any other throttle position. |
AUTOSTICK OVERRIDE SHIFT SCHEDULE
Scheme 2
Overview
42LE transaxle shift schedule depends on temperature of transaxle fluid. The shift schedule is modified to extend life of transaxle while operating under extreme conditions. Transaxle fluid temperature is measured by transmission temperature sensor, located in Transmission Range (TR) sensor.
If transmission temperature sensor fails, TCM will default to a calculated fluid temperature which is calculated from a combination of inputs. Calculated fluid temperature is continually updated and retained in memory for 20 minutes after ignition switch is turned off. When vehicle is started after an extended OFF time, calculated fluid temperature is reinitialized at a value between battery temperature and engine coolant temperature signals received from PCM. Calculated fluid temperature may become inaccurate during extreme operation, causing incorrect shift schedule. Highlights of various shift schedules are as follows
Differential bearing rotating torque must be checked when any of the following components are replaced: transaxle case, differential bearings, inner and outer bearing adjusters with bearing races, differential bearing support or differential case. Differential bearing rotating torque should be performed only with NEW differential bearings. Inner and outer bearing adjusters and transfer shaft bearings must be replaced if differential bearings are replaced. DO NOT use this procedure with used differential bearings. Manufacturer does not list differential bearing rotating torque with used differential bearings. Differential bearing torque must be checked with transfer shaft removed from transaxle case.