Manufacturer communication — 2006 GMC YUKON DENALI XL

• 2014 and prior GM passenger cars and light duty trucks.

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  Models: 2014 and Prior GM Passenger Cars and Light Duty Trucks

• On automatic transmission vehicles, a clunk noise when shifting between Park and Drive, Park and Reverse, or Drive and Reverse.

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  Some customers of vehicles equipped with automatic transmissions may comment that the vehicle exhibits a clunk noise when shifting between Park and Drive Park and Reverse, or Drive and Reverse.

• A clunk noise while driving when the accelerator is quickly depressed and then released.

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  Similarly, customers of vehicles equipped with automatic or manual transmissions may comment that the vehicle exhibits a clunk noise while driving when the accelerator is quickly depressed and then released.

Possible causes

• Gear clearance or freeplay (lash) can produce a clunk whenever a gear is loaded and unloaded quickly or the direction of rotation is reversed.

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  This clearance or freeplay (also known as lash) can translate into a clunk noise whenever the gear is loaded and unloaded quickly, or whenever the direction of rotation is reversed.

• In a 4-wheel drive vehicle the transfer case gears and their clearances add freeplay on top of that from the rear axle gears, universal joints and transmission.

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  This is because in addition to the freeplay from the rear axle gears, the universal joints, and the transmission (common to both vehicles), the 4-wheel drive transfer case gears (and their associated clearances) add additional freeplay to the driveline.

Steps to confirm (in the document’s order)

• Compare the complaint vehicle with a like vehicle; if the results are the same, it is a normal condition.

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  Note: Compare this complaint vehicle to a like vehicle. If the results are the same, this is a normal condition.

Caution

• Because every driveline component has some lash by design, changing driveline components may not reduce the lash satisfactorily.

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  Because all of the components in the driveline have a certain amount of lash by design, changing driveline components may not result in a satisfactory lash reduction.

• The clunk noise does not adversely affect durability or performance.

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  While some owners may find the clunk noise objectionable, this will not adversely affect durability or performance.

• Do not confuse this with the clunk at stop or from launch that is handled by cleaning/lubricating the rear propshaft slip yoke splines (Corporate Bulletin Number 09-04-21-003D or later).

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  Clunk Noise at Stop or From Launch (Clean/Lubricate Rear Propshaft Slip Yoke Splines) (Corporate Bulletin Number 09-04-21-003D or later)