I have a 1991 Cherokee. In recent weeks I have installed a 6.5" Pro Comp lift and a new track bar. My Jeep drove fine until yesterday when I installed a longer Pitman arm to replace the stock one because of the lift. I test drove it after the Pitman arm install and it seemed fine. Tonight I was headed home from a friend's house working on a cb install and when I got up to about 45mph the front end started shaking really bad. I got down to 40mph and it went away. I don't know if this is death wobble or not since I'm new to Jeeps. I am running Goodyear Wrangler 31s on stock alloy wheels. The tires are in need of replacing but this hasn't occurred since I bought the Jeep about two months ago until tonight. It also needs an alignment but it has needed an alignment for about two weeks. Any input would be greatly appreciated!

 

You dropped the pitman but did you also drop the TB?

 

Are you on short arms without drop brackets? If so, that is a can-of-worms in itself.
A drop pitman will usually cause bump-steer.
You will need to adjust the caster first, then toe. Then test drive.
http://go.jeep-xj.info/HowtoAlignment.htm

 

I would start with the alignment and then see how it drives. Is it fair to assume your lift kit came with a new steering stabilizer?

 

Agreed on the note below about the drop on the trac bar...post a pic of the front end between the wheels straight on shot. Plus it's not worth chasing your tail when you haven't had it aligned after a big lift like that.

 

Thanks for all the info! I took it to a friend's house who has experience in this and we found the major problem. We had installed a heavy duty track bar when we installed the lift and we made sure that everything was tight but the nut on the track bar joint on the driver side came loose. Way loose! I got a video but I'm not sure how to embed it to show you. The tie rod end that connects to the Pitman arm also has a joint that is slight bad but is still drivable. So, after tightening the nut on the track bar I took the 20-minute home and was able to get up to the 50mph speed limit without any issues!