I just bought a 93 cherokee 4x4 with a 4.0, but it has some issues. I took it on the interstate for the first time and at 70mph the front end starts to shake. At first I thought it was something to do with the front suspension. But reading online, I'm starting to think maybe it's the front drive shaft. There is quite a bit play in it. The U joints seem OK. It seems to me that the play is in the transfer case and the front differential. Could this cause the shaking? Is this normal or a big problem? If it is the problem how can I fix it?
The other problem I have is under semi hard to hard braking. It feels like the brakes engage and let go, on and off. Causing shaking. I noticed the relay for the abs is missing. Any help would be appreciated. Thanks in advance.

 

If I had to make a guess based on limited information I'd say badly warped rotors.

 

Would this cause the shaking at high speed or just the braking problem? Is it something i can diagnose myself?

 

remove the front drive shaft and take it for a drive. if the problem goes away you either have a problem with the driveshaft or the output on the tcase. it will be easier to diagnose either with the front shaft removed, there should be no side to side or in and out play in the yoke on the tcase. it may rotate a bit back and forth but it should not move otherwise. same goes for the yoke on the axle.

as for the braking problem I agree with lowrange it could be a warped rotor. do you have an ABS pump under the hood? if not that is why there is no relay in the ABS hole in the fuse box.

 

I do not believe my eyes.

The rotors could certainly cause the brake pulsing issue. Pull the wheels off and have a look at the rotors. It will be obvious that they're worn.

Do what ^ he said to diagnose the vibes at speeds.

 

Thanks for the reply's. I'll probably pull off the wheels and have a look at the rotors, as well as check whatever else i can (wheel bearing,ball joint etc). Maybe the high speed shaking is due to something like that. If i don't find anything, I'll pull the front drive shaft and see if that is the problem.

 

I would also look at the basics, such as tires being out of balance. I just recently had new tires put on, and couldnt belive the difference it made. I thought I had the beginnings of death wobble, because of the 206,000 miles on her, but the new tires/balance/etc cleared up any shaking I had going on!