Subject: | Rubbing, Whirling or Squeal Noise from the Front of the Transmission |
Models: | 2007 Chevrolet Silverado |
2007 GMC Sierra |
Equipped with 6L90 Automatic Transmission (RPO MYD) |
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Rubbing, whirling or squeal noise from the front of the transmission. This noise will be most audible in 1st, 2nd, 3rd and 4th gears at approximately 50% TP, engine speed of 2,000 - 2,500 RPM and TCC not applied. When the noise occurs a Tech 2 will show torque converter slip speed of typically 200 - 400 RPM and the noise will last 1 - 2 seconds. The noise will stop and not occur when the TCC is applied. Vehicles with this noise issue will be very low mileage and the noise will probably be noted during unloading from the transport or during PDI.
This noise may be caused by insufficient clearances inside the torque converter. Changes were implemented in vehicle production January 30, 2007 to prevent this noise from occurring.
If this noise condition is encountered please contact TAC at the phone number you have been provided.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.