The 4T40-E transmission uses a line pressure control system, which has the ability to continuously adapt the system line pressure. This compensates for normal wear of the following parts:

The PCM maintains the Upshift Adapt parameters for the transmission The PCM monitors the AT ISS sensor and the AT OSS during commanded shifts in order to determine if a shift is occurring too fast or too slow. The PCM adjusts the signal from the transmission pressure control solenoid in order to maintain a set shift feel.

Transmission adapts must be set again when the transmission is overhauled or replaced. In order to set the transmission adapts again, select the following:

1. Tech 2
2. Special Functions
3. Transmission Output Controls
4. Clear TAP