The 4L80-E transmission uses a line pressure control system,
which has the ability to continuously adapt the system's line pressure. This
compensates for normal wear and break in of the following parts:
| • | The clutch fiber plates |
The VCM/PCM maintains the following adapt parameters for the transmission:
| • | Upshift Adapt - The VCM/PCM monitors the Automatic Transmission
Input(Shaft) Speed Sensor (A/T ISS) and the Output Speed Sensor (OSS) during
commanded shifts in order to determine if a shift is occurring too fast or
too slow. The VCM/PCM adjusts the signal to the transmission pressure control
solenoid valve in order to maintain a set shift feel. |
| • | Steady State Adapt (Diesel only) - The VCM/PCM monitors
the Automatic Transmission Input(Shaft) Speed Sensor (A/T ISS) and the Output
Speed Sensor (OSS) after a shift in order to calculate the amount of slippage
in that gear. The VCM/PCM then adjusts the signal to the Transmission Pressure
Control Solenoid signal in order to maintain slippage below a set amount. |
Reset the Transmission Adapt functions when the transmission is overhauled
or replaced. To reset the Transmission Adapt functions, use the Scan Data
tool.
