rayray311

Hey Guys....i seem to al,ways get the best answers and ideas from you guys. I have a 99 cherokee INline 6. It has a 4.5 inch lift with 31 all terrains on it. I got it 2 years ago off a fireman who was the original owner who had all regularly scheduled maintenance done at the dealer. The Jeep had its whole rear end/axle replaced after only one year due to a defect in the original. Since then it had no problems.

I spent 6 months travelling thru northwest mtns with a full loaded Jeep and also pulling a pop up camper. Everything seemed to be going fine until I started hearing a vibration or grind upon every rotation at the same spot or moment...which seemed to be coming from the left rear tire. I assumed I had a break problem. About 6 months beforehand I had the rear drums, pads and calipers replaced. I assumed a brake pad was sitting wrong and grinding on each rotation. I pulled off the tire and saw no problem.

I took it to my mechanic to check it out along with telling him to check out a modest hum that was coming from underneath the Jeep. I was thinking that the driveshaft U joint was going out also. 2 mechanics at this shop checked it out and saw no U joint driveshaft problem. And no problem with my brakes or anything on that tire. He said he did some slight adjustments to the cables/parts in the rear left brake.

The rotational grind/hum seemed to go away but within about 8 hrs it returned. Also I noticed it would sometimes be worse than other times. I also noticed that this only happened near the tail end of braking right before I stopped and that if I slowed down slow enough I could feel a type of "hump" each time I heard the sound with every rotation at the same exact spot.

Beyond this the mechanic said my transfer case probably needed to be replaced soon but could last a while longer. Said it was missing a bearing. They serviced the transfer case for me and just got it fresh fluids etc.

These mechanics were baffled by this rear left tire grinding feeling...said it might be related to that transfer case issue actually.

Input? Ideas?
Ray

SeriousOffroad

Missing a bearing?
Doubtful....very doubtful.

Missing some useful info from your first post

What rear axle do you have?
What transfer case?
What transmission?
Gear ratio?
Mileage?
SYE?

Whats your rear pinion angle?

textherex

I would have to say Bearing. Or a dragging Brake shoe. That is about all that will grind at the wheel.

rayray311

ill get all that info and post ti when i get home today....

rayray311

BTW...how do i determine what type of trasfer case, gear ratio etc that i have? i can most likely look up the receipt from when they put new rear end on Jeep to see what axle it is etc...but i dont know how much it will tell me. it has 132k miles on it
and the brakes were checked 3 times with no problems found

99superjeep01

Easiest way to check the gear ratio is to jack up the rear end, mark the driveshaft somehow, spin the tires and count the rotation. If it spins 3.5 times you've got 3.55 gears. This will most likely be it. If it spins about 3 3/4 times you've got 3.73 gears. As for the t case, this is easy. Look at the back of it to the left of the driveshaft and you'll see a tag. It'll start with either an NP or an NV and end with a 231 or 242.

99superjeep01

And you'll most likely have a 8.25 rear axle. They came stock in the 99's and they have a flat bottom. (Flat bottom Jeeps you make the rockin' world go round!) Sorry that was terrible but it made me chuckle.