Second Order Propshaft Vibration or Launch Shudder - keywords angle boom driveline drone moan noise

This PI is being superceded to add the important note. Please discard PIP4352.

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

Customers may comment that the vehicle exhibits a vibration typically at speeds of 40 mph and up with the vehicle loaded and or unloaded. Customers may also comment that the vehicle may exhibits a launch shudder with the vehicle loaded and or unloaded. Technicians may find a 2nd order prop shaft vibration when using the EVA.

Important note: DO NOT replace the transfer case for the above condition.

Both of the above vibrations may be caused due to the driveline working angles not being optimum. Make sure to adjust the working angles in a position that will best suit the customers operating conditions, i.e. if loaded adjust the angles with the vehicle loaded vs. unloaded and vise-versa.

Measure the driveline working angles. Adjust the front non-canceling working angle to between 1.5 and.5 degree total. Adjust the center and rear canceling working angles to within.5 degree of each other.

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.