2kSi

got a 2001 jeep cherokee that vibrate bad( like a propeller) when engage 4 wheel(higher the speed the faster the vibe). When place back in 2wd it still vibrate bad(only when moving) until driven reverse 50 feet and it goes away or remove the front drive shaft(which is brand new). Shop said it was the axle and driveshaft but replace all of it and it still the same. Any idea??

Fabrik8

What is vibrating? Is it an engine vibration that is there whether you're moving or not, or regardless of the speed, or is it a driveline vibration that you only feel while moving?

Kris.Is.Foamin

Is it lifted?

-JB-

So the front shaft is new? Ujoints are in and have not worked their way out? I had a retaining clip come off and my cap started walking out causing a vibration.

If you remove the front driveshaft and the vibration goes away can say that it's in the front and that the rear is fine. Because these Jeeps have a live front end, by that I mean when the front shaft is in, the transfer case is in 2wd the front shaft will still turn because the wheel hubs have no way to be disconnected via a lock out hub. When dealing with a front end vibration, removing the shaft will help determine the issues. If the vibration goes away 9 times out of 10 it's the shaft or the pinion in the front axle or the output shaft on the transfer case. Put the shaft back in and push up and down on the shaft to see if there is any movement when you push. If so you found your vibration.

Sometimes vibrations in the front can be because of suspension and usually the control arm bushings are shot, causing the arm to vibrate against the mounts.

2kSi

There is no shaking or vibration at all, until engaged in 4wd. So its not the front driveshaft cause it spins all the time. Once it vibrate or shake like a helicopter, the faster i drive the faster the vibration. No shaking when not moving. Still shake when put back in 2wd until driven reverse 50ft or remove the front drive shaft. So i do believe its the output shaft on the transfer case or the other side the drive shaft connects to. Oh yea i cant select 4wd lo, only 4wd and 4wd part time..

JDM74

It has to be downstream of the vaccuum disconnect in the front axle. The driveshaft and one side of the front axle spin all the time. The disconnect is in the long side of the axle and is a collar that locks that side to the center section. Judging by what you have told us the vibration source has to be down stream of that connection or the connection itself. The X-case not going in 4-lo is another issue.

-JB-

Not all Jeeps came with the d30 vacuum disconnect axle and his being a 2001 he shouldn't have one. I'm thinking he has a problem with the tcase or the pinion on the axle. He only has this problem when applying torque to the front end aka in 4wd. In 2wd an being a live front end you would get vibes out of the front shaft from the ujoints or vibes from the axle ujoints. This is always the case with front vibrations, however since he has described it when torque is applied and he gets a vibe I'm thinking tcase or pinion would be my first things to check.

2kSi

yep no vacuum disconnect. I would figure its the t case output or the other case that the front drive shaft connect to that connect the front axle, but dunno how to trouble shoot it without replacing them to figure which is the problem

-JB-

Put the shaft back in. Push up and down on it to see if anything moves. Do you hear any type of noises out of the tcase? When you say new driveshaft, do you mean a brand new one never run before?

JDM74

Guess my source was in error. It led me to believe that all the XJ's came with a vacuum disconnect D30. My bad. In that case I agree with your diagnosis of pinion or X-case output. Thanks for the info.