Information On 2-3 Upshift Or 3-2 Downshift Clunk Noise (01-07-30-042H)
Publication date: 2014-01-14Reference number: 01-07-30-042H
Supersedes refnos: 01-07-30-042, 01-07-30-042A, 01-07-30-042B, 01-07-30-042C, 01-07-30-042D, 01-07-30-042E, 01-07-30-042F, 01-07-30-042G
INFORMATION ON 2-3 UPSHIFT OR 3-2 DOWNSHIFT CLUNK NOISE
TECHNICAL SERVICE BULLETIN
Reference Number(s): 01-07-30-042H, Date of Issue:
January 14, 2014
Superceded Bulletin(s): 01-07-30-042G, Date of Issue:
September 22, 2011
| Affected Model(s): | 2014 and Prior GM Passenger Cars and Light Duty Trucks Equipped with 4L60-E, 4L65-E or 4L70-E Automatic Transmission (RPOs M30, M32, M70) |
| Supercedes: | This bulletin has been revised to add the 2013-2014 model years. Please discard Corporate Bulletin Number 01-07-30-042G. |
SERVICE INFORMATION
IMPORTANT:
For 2005 model year fullsize utilities and pickups, refer to Corporate Bulletin Number 05-07-30-012 .
Some vehicles may exhibit a clunk noise that can be heard on a 2-3 upshift or a 3-2 downshift.
During a 2-3 upshift, the 2-4 band is released and the 3-4 clutch is applied. The timing of this shift can cause a momentary torque reversal of the output shaft that results in a clunk noise. This same torque reversal can also occur on a 3-2 downshift when the 3-4 clutch is released and the 2-4 band applied. This condition may be worse on a 4-wheel drive vehicle due to the additional tolerances in the transfer case.
This is a normal condition. No repairs should be attempted.