TSB 08-07-30-026 (S: A/T - Slight Vehicle Movement In Park At Start Up

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INFORMATION Bulletin No.: 08-07-30-026A Date: May 17, 2011 Subject: Information on Slight Vehicle Movement in Park at Start Up After Cold Soak Models: 2012 and Prior GM Passenger Cars and Light Duty Trucks Equipped with Automatic Transmission Supercede: This bulletin is being revised to add the 2010-2012 model years. Please discard Corporate Bulletin Number 08-07-30-026 (Section 07 - Transmission/Transaxle). Some vehicles may rock or move slightly forward or rearward while in park at start up after cold soak. This condition may be accompanied by a clunk noise. This is a slight movement that is more often seen visually, rather than felt, when viewed from the outside and using the auto-start feature, if equipped. This slight movement is due to the residual transmission fluid in the clutch packs that creates a partial apply on start up. This movement is stopped by the parking pawl and/or transmission fluid exhausting completely from the clutch packs. This slight movement has no adverse affects on the transmission and no repair should be attempted. This condition is normal. This can be verified by comparing with another identically built vehicle under the same cold conditions. To prevent this condition from occurring, the parking brake should be utilized as per the Owner's Manual recommendations anytime the vehicle is parked. Disclaimer