Hey guys, I am having some small vibrations after my 3 inch lift on my 2000 xj. I put a t-case drop of 1 inch. I just measured my angles and was wondering if these angles are acceptable. The front is 11 degrees; driveshaft is 16 degrees; and pinion is 9 degrees. Thanks Phil

 

TTT

I'm wondering the same thing, since I have a 3" lift on it's way.
BTW, what did you use to measure the angles?

Thnks.

 

With a single U-joint at each end of the driveshaft, the pinion angle MUST be parallel with the transfer case output, so each u-joint cancels the vibes from the other.



If you have a sye and a double cardan at the transfer case, you point the pinion directly at the transfer case so you have 0* difference between the pinion angle and driveshaft angle, meaning your pinion is pointed higher



The front axle pinion angle needs to be balanced with castor, with pinion taking priority. The front axle pinion should be adjusted parallel with the driveshaft, and steering checked. If the steering took a big hit, back off the pinion little by little till you reach an angle that works for both steering and vibration

 

Thanks to the above poster that is the best diagram I have seen. Going to recheck angles and we will see.

 

How are you measuring angles? I mean, literally, how do you do it?

 

Use an Angle Finder. Search my build thread for "angle finder", theres a couple pictures too. I did a little measuring here and there for the rear pinion and drive shaft angles. I even recently started measuring the front angles.

 

I read your excellent thread on your 4.5" RC build. First class work - on the XJ and the thread. In fact, it's the best install thread I've read (hey...that rhymes).

One question - when you finished the rear axle pinion adjustment, you wound up with 15 degrees on the DS and 13 on the pinion. Do you have any vibration or is that 2 degree spread acceptable?

 

Thank you for the kind words sir!

I have no vibration at all from the rear drivetrain. 2 degrees of separation between the pinion and drive shaft are no problem at all. In fact, most recommend a couple degrees of separation between these angles to compensate for axle wrap, changes in the angles due acceleration.

And, I guess you're a poet and didn't know it!

 

NVM