The run out of the drive shaft should also be checked. If there is excessive run out, determine the cause and make
the necessary repairs. If the run out is fine, check the phasing of the joint's and their angle. To check their operating
angle, use an inclinometer. This instrument, when attached to the drive shaft, displays the angle of the drive shaft along
any point. Your finding from this test should be compared to specifications. Normally, if the angles are wrong, the
rear axle has moved in its mounting.
As a final diagnosis inspection point, check the entire length of the drive shaft for excess undercoating, dents, missing
weights, or other damage that could cause an imbalance and result in a vibration. If no damage is found, the drive
shaft should be removed and its balance checked by a specialty shop.
When a U-joint is damaged or excessively worn, it must be replaced. Photo Sequence 38 covers the typical
procedure for removing a U-joint from a drive shaft. After
a replacement joint is obtained, it needs to be installed.
Photo Sequence 39 covers the reassembly of a common U-joint.