08-07-30-026C

Bulletin No.: 08-07-30-026C
Date: Mar-2016
Subject:
Information on Slight Vehicle Movement in Park at Start Up After Cold Soak
Models:
2016 and Prior GM Passenger Cars and Light Duty Trucks
Equipped with Automatic Transmission
Attention:
This Bulletin also applies to any of the above vehicles that may be Export vehicles.
This Bulletin has been revised to add the 2015 and 2016 Model Years. Please discard Corporate Bulletin Number 08-07-30026B.
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 condition is normal and no repairs should be attempted. This can be verified by comparing with another identically built vehicle under the same cold
conditions.
Customer Information
Please communicate to the customer this condition is a normal operating characteristic of the vehicle. This slight movement has no adverse affects on the
transmission. To prevent this condition from occurring, the parking brake should be utilized as per the Owner's Manual recommendations anytime the vehicle is
parked. Please share this information with the customer including a copy of this message.
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may
occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools,
safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that
your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
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