Jeep Question-3-1/2" Lift But Has Vibration

You will find that the accute angles the drive shafts are operating will give you vibration and longevity issues.

I've put here some forum sites which you will find beneficial, not just for your immediate problem but for the future issues.

http://www.outerlimits4x4.com/index.php

http://www.pirate4x4.com/forum/index.php

http://www.jeepforum.com/

http://www.jeepforums.org/

http://www.wranglerforum.com/

If you do a search on those forums you will find several threads that deal with you issue.

Hope that helps

Thanks a lot! Great info!

Sounds like your pig (differential) is out of plane with the drive line. Or put better, the pinion shaft center line is out of alignment with the tranny tail shaft center line.

The links Tobugrynbak will help you resolve this.

Years ago, I had a Ford F150 that I added a 6" lift kit. The kit was a cheepy and the spring blocks were squared. I brought the old angled blocks and new ones to a machine shop and they machined them to the proper angle, taking into account the additional lift and that solved the problem.

Good Luck!

The output shaft of your transfer case needs to be parallel with the pinion shaft of your axle. Don't worry about the steep angle of the drive line unless it is binding in the u-joints. The most important thing is being parallel. The more it is out of parallel the more vibration you will get.

Interesting information. Thanks!

I've seen what you are talking about but never knew if they were worth the expense. It sounds as if they are.

Thanks!

the prop shaft does not have constant velocity joints but the front wheel drive axle would have at the wheel ends

the prop shaft joints can only take a small drive angle as the hooke coupling when rotated through a large angle goes fast slow fast slow in one revolution unlike the CV joints which can take extreme angels and maintain velocity throughout hence the name contstant velocity

perhaps this is causing your problems

http://en.wikipedia.org/wiki/Universal_joint

I think that I remember the limit for U joints was 7.5 degrees. The angle should be the same at each end. The CV joint may be required, I will yield to the experts there. But this I do know, if you pulled apart the slip joint in the middle of a driveshaft, you MUST align the U joints. Most split shafts have an alignment deformation to ensure that it is aligned, but if the shaft was lengthened to allow for the lift kit, it might have been eliminated. Check that before digging in it too much. Good luck.