Oriented u-joints??

[Crazy440]

What is meant by this? And, how do I do it? Getting ready to install my new driveshaft. Have a 8 3/4 rear and I just installed new springs. What's the correct pinion angle I should set it at?
Thanks

[Paul G]

Both u joints have to operate on the same plane. Meaning if one u joint is operating on the horizontal axis, the other has to be exactly in phase with it. To simplify, if one is swinging up and down, the other must be swinging up and down. If they are slightly out of phase it can cause vibration.

As for pinion angle, for a street car they should be both equal and opposite. If the front is say, 2° downward, the rear should be 2° upward. The u joint needs to have at least 1/2° operating angle so the needles rotate. Not so much an issue with Mopar since the engine/trans sits off center to the passenger side in the chassis.

Racers like to have a few more degrees downward angle on the diff. So under hard acceleration the diff will point up toward the trans and put the u joint angles more equal. Not intended so much for a street car.

[John_Kunkel]

U-joint "orientation" is different from u-joint "angle".

Orientation deals with having the u-joints in phase, this only becomes an issue when building a driveshaft or when multiple shafts are used in one installation.