Transmission Adaptive Functions 5L40-E
The Hydra-Matic 5L40-E uses a line pressure control system which has the ability to adapt the system line pressure in order to compensate for normal wear of clutch fiber plate, seals, springs, etc. The adaptive feature is similar in function to fuel control (integrator/block adapt).
The Hydra-Matic 5L40-E transmission uses the adaptive function for garage shifts, upshifts, and TCC application. The TCM monitors the input shaft speed in order to determine if the shift is occurring too fast or too slow and adjusts the pressure control solenoid in order to maintain the correct shift feel.
Shift Adapt Relearn Procedure
Perform Transmission Adaptive Relearn Procedure after the following service procedures.
| • | Transmission replacement or major components overhaul |
| • | TCM replacement or reflashment |
| • | Valve Body Replacement |
After completing the repair, you must delete the adaptive values. These units are needed to refill for the optimal shift quality. Only pay particular attention to coast downshift in the following steps.
Coast Downshift Adapt Procedure
- Drive the vehicle in Drive 5 for normal transmission operating temperature.
- Drive the vehicle at 73 km/h (45 mph) and apply the brake until it stops for 13 seconds.
- Drive the vehicle at 73 km/h (45 mph) and apply the brake moderately until it stops for 6 seconds.
- Drive the vehicle at 40 km/h (25 mph) and then coast at 8 km/h (5 mph).
Repeat the previous steps three times.
Follow the diagnostic steps or repair process totally to complete each step. If the conditions have been corrected before having performed all the steps, it is unnecessary to perform the remaining steps.
