So tried a search, but I couldn't really find much that will help.

Quick intro. Its 99 Cherokee with a RC 4.5" lift. No long arms, no SYE. I purchased it this way. It does have a TC drop. 32"x11.50 tires, less than a year old.

This issue just started 2-3 days ago and its really strange. I have not done any off roading in a few months and this concern seemed to manifest just out of the blue one day while cruising around town.

On to the problem. I noticed under light acceleration from a stop, there is a slight vibration. It doesn't feel like wheel imbalance. As soon as I let off, it stops.
No onto the freeway. This is where it can really be felt. Cruising at 65 mph, either on flat ground with light throttle or up hill. Basically any time the throttle is slightly applied, it happens. it will come and go at a consistent interval. It will vibrate for a few seconds and then fade out for a few seconds, then fade in and vibrate for a few second and fade back out. If i let off the throttle, it immediately stops and feels nice and smooth even at 75 mph. As soon as I apply light throttle, it returns. It is a very fast, but no harsh vibration. It doesn't shake the whole jeep, but you can hear the buzz in the plastics in the interior and feel it in the seat and steering wheel.

Almost like a video game controller, the way it vibrates.

any help or advise is appreciated. Maybe some of you have run into the same thing.

I guess what is really stumping me is that it came out of no where.

 

With 4 1/2" of lift it should have an SYE not a TC drop kit. But check the u-joints first and lube them if you haven't.

 

Thanks, and thats what I have heard. I will install one in the future for sure. Would not having it cause this problem just out of no where?

 

So I may have answered my other concern that I posted about. Pretty gnarly ATF leak coming somewhere between the bac of the trans/front of the T-case.

https://www.cherokeeforum.com/f2/tra...d-leak-228781/

After some research, I have read that a failing U-joint can cause a rear output shaft seal to go bad and start spewing ATF. Sounds like I have both of these issues going on.

Quick question though. Can a bad U-joint cause a rear output shaft seal on the trans to go bad, even though a T-case is in between there.