Harsh, Soft, or Erratic Shift Quality After Transmission Repair, Erratic Line Pressure

This section contains bulletins and pertinent information for installers or repair facilities. Many of the bulletins in this section deal with very common installation or unit problems. Always check for pertinent bulletins before beginning any installation or if a problem occurs with a unit. Check back often. We add bulletins as information becomes available. If you have any questions please call the warranty department at 800-841-6060 or email us at warranty@dahmerpower.com.
Harsh, Soft, or Erratic Shift Quality After Transmission Repair, Erratic Line Pressure
Problems After Transmission Repair
4T65E
Harsh, Soft, or Erratic Shift Quality After Transmission Repair, Erratic Line Pressure

Whenever repair work is done on the transmission, the adaptive memory needs to be reset to avoid erratic shift quality and line pressure control. This is critical because the pump life can be shortened or the pump damaged by the computer commanding maximum steady state line pressure because of an old adaptive value stored for a previously missing gear, such as when the 4th clutch hub strips out.

The shift quality may adapt and feel ok, but the steady state adapts are updated very slowly, especially when “learning down” , or reducing line pressure.

To clear the transaxle adapts, either use the adaptive reset function on your scan tool, or alternately use the following procedure:

• Disconnect the battery, or unplug the PCM, and wait at least two hours before reconnecting.