Groan Noise From Launch Or At Stop - keywords bump clunk moan pop squawk

This PI is being superseded to change repair recommendation. Please discard PIP4020.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Some customers may comment that their new body style 4WD-full size pickup makes a groan noise at parking lots speeds on launch or with light to medium braking. Braking to a complete stop can force the propshaft slip yoke forward into the transfer case while the vehicle rebounds slightly backwards after stopping its momentum and create this noise.

Note: This PI does not apply to the Silverado or Sierra classic versions.

Root cause may be the interface between the rear propshaft slip yoke and the transfer case output shaft splines. Testing indicates that this condition is exhibited at low mileage and goes away after approximately 200 miles. To isolate the concern is the slip yoke and not a brake noise the dealer may attempt to duplicate while coasting with the transmission in neutral and braking to a stop. If the noise is gone while braking in neutral the noise is NOT brake related noise. Dealers may lube the slip yoke splines with TransGel (J36850) to help reduce the noise.

The slip yoke spline interface is initially dry, so part of the break-in involves a distribution of the ATF fluid.

Note: This PI does not apply to the Silverado or Sierra classic versions.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.