Information on 2-3 Upshift or 3-2 Downshift Clunk Noise TECHNICAL SERVICE BULLETIN Reference Number(s): 01-07-30-042E, Â Date of Issue: Â May 21, 2007 Affected Model(s): 2008 and Prior Passenger Cars and Light Duty Trucks; 2003-2008 HUMMER H2; 2006-2008 HUMMER H3; 2005-2008 Saab 9-7X; with 4L60-E, 4L65-E or 4L70-E Automatic Transmission (RPOs M30, M32, M70) Supercedes: This bulletin is being revised to add the 2008 model year and 4L70E transmissions. Please discard Corporate Bulletin Number 01-07-30-042D (Section 07 - Transmission/Transaxle). Related Ref Number(s): 01-07-30-042, 01-07-30-042A, 01-07-30-042B, 01-07-30-042C, 01-07-30 -042D, 01-07-30-042E ARTICLE BEGINNING SERVICE INFORMATION IMPORTANT: For 2005 model year fullsize utilities and pickups, refer to Corporate Bulletin 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. Page 1 of 1 Information on 2-3 Upshift or 3-2 Downshift Clunk Noise -1999 Chevrolet Suburban K15.
Not sure but it sounds like you are describing this?
Tranny shop may be able to make an adjustment to lessen this effect.
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