IDENTIFICATION OF SYSTEM
The 41TE Transmission family can be identified through a visual inspection. Confirm the presence of a Solenoid/Pressure Switch Assembly, Transmission Range Sensor, Input Speed Sensor and Output Speed Sensor all located on the same side of the transmission case. Refer to 41AE/TE TRANSAXLE for transmission ID tag descriptions.
GENERAL DESCRIPTION
The 41TE electronic transaxle is a conventional transaxle in that it uses hydraulically applied clutches to shift a planetary gear train. However, the electronic control system replaces many of the mechanical and hydraulic components used in conventional transmission valve bodies.
FUNCTIONAL OPERATION
The 41TE electronic transaxle has a fully adaptive control system. The system performs its functions based on continuous real-time sensor feedback information. The control system automatically adapts to changes in engine performance and friction element variations to provide consistent shift quality. The control system ensures that clutch operation during upshifting and downshifting is more responsive without increased harshness.
The control module continuously checks for electrical problems, mechanical problems, and some hydraulic problems. When a problem is sensed, the control module stores a diagnostic trouble code.
Some of these codes cause the transaxle to go into Limp-in or default mode. While in this mode, electrical power is removed from the transaxle, deenergizing the transmission control relay, and solenoid pack. When this happens, the only transaxle mechanical functions are
Park and Neutral
Reverse
Second Gear
No upshifts or downshifts are possible. The position of the manual valve alone allows the three ranges that are available. Although vehicle performance is seriously degraded while in this mode, it allows the owner to drive the vehicle in for service.
Once the DRBIII® is in the Transmission portion of the diagnostic program, it constantly monitors the control module to see if the system is in Limp-in mode. If the transaxle is in Limp-in mode, the DRBIII® will flash the red LED.
TRANSMISSION OPERATION AND SHIFT SCHEDULING AT VARIOUS OIL TEMPERATURES.
The transmission covered in this article has unique shift schedules depending on the temperature of the transmission oil. The shift schedule is modified to extend the life of the transmission while operating under extreme conditions.
The oil temperature is measured with a Temperature Sensor on the 41TE transmission. The Temperature Sensor is an integral component of the Transmission Range Sensor (TRS). If the Temperature Sensor is faulty, the transmission will default to a calculated oil temperature. Oil temperature will then be calculated through a complex heat transfer equation using engine coolant temperature, battery/ambient temperature, and engine off time. These inputs are received from the PCI bus periodically and used to initialize the oil temperature at start up. Once the engine is started, the control module updates the transmission oil temperature based on torque converter slip speed, vehicle speed, gear, and engine coolant temperature to determine an estimated oil temperature during vehicle operation. Vehicles using calculated oil temperature, are reasonably accurate, during normal operation. However, if a transmission is overfilled, a transmission oil cooler becomes restricted, or if a customer drives aggressively in low gear, the calculated oil temperature will be inaccurate. Consequently the shift schedule selected may be inappropriate for the current conditions.