Manufacturer communication — 2006 GMC YUKON DENALI XL

• Applies to 2016 and earlier GM passenger cars and light duty trucks equipped with an automatic transmission.

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  Models: 2016 and Prior GM Passenger Cars and Light Duty Trucks Equipped with Automatic Transmission

• At start up after a cold soak, the vehicle may rock or move slightly forward or rearward while in Park, sometimes with a clunk noise.

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  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.

Possible causes

• Residual transmission fluid in the clutch packs creates a partial apply on start up.

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  This slight movement is due to the residual transmission fluid in the clutch packs that creates a partial apply on start up.

• The movement stops when the parking pawl holds and/or the fluid exhausts completely from the clutch packs.

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  This movement is stopped by the parking pawl and/or transmission fluid exhausting completely from the clutch packs.

Steps to confirm (in the document’s order)

• Verify by comparing with another identically built vehicle under the same cold conditions.

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  This can be verified by comparing with another identically built vehicle under the same cold conditions.

Repair

• To prevent the movement, apply the parking brake whenever the vehicle is parked, as the Owner's Manual recommends.

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  To prevent this condition from occurring, the parking brake should be utilized as per the Owner's Manual recommendations anytime the vehicle is parked.

Caution

• The condition is normal and no repairs should be attempted.

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  This condition is normal and no repairs should be attempted.

• The slight movement has no adverse effect on the transmission.

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  This slight movement has no adverse affects on the transmission.