91cavgt

This is my first post here, and I'm already in desperate need of help!!

I just purchased a 1995 Jeep Cherokee Limited with the 5.2 V8. Upon driving it home, about 2 miles from my house I came to a stop and smelled the nasty burned diff fluid smell. So I baby it a little further since I'm almost home but about 1/2 mile from my house the diff starts making some horrible grinding noises.

It made it to my house going really slow with hazard lights on.


I am a mechanic by trade, but a diesel mechanic not an automotive mechanic so I need some guidance here.

The rear diff was smoking hot. The only thing that makes sense to me is that the rear diff was low on fluid when I bought it tonight and the highway trip home pretty much overheated it and caused it to shell.

The front diff was really hot to the touch as well (heard my wet finger sizzle when I touched it). Is this normal after a 50 mile highway trip? Where should I start on diagnosing to make sure it's just the rear diff and not more than that?

I did test drive the Jeep before I bought it and it did great. No strange noises and I tested out the low range as well, it worked fine too. Please help!!!!!

newtownhood

I heard something about transfer case issues that cause the rears to basically fight eachother. The rears get super hot. I'd try to go through all the ranges on the transfer case and see what happens...Sadly, you'll probably need all new axle seals if both rears got that hot...goodluck.

chrisdm4

Pull the covers and take a look in side the diffs and see what is going on in there.

91cavgt

The only ranges on the transfer case are AWD and 4WL. I went through those when I bought it and it did fine. There is definately something broken though as there was some major grinding going on when I turned down my street. The Jeep also slowed down a lot when I just let off the gas, it was like I was on the breaks.

91cavgt

That's the first thing I'll be doing tomorrow morning.

twinkdog586

when my 95 did that i had a broke axles but it could be something else good luck

91cavgt

Well, I pulled the rear diff cover off and it is perfectly fine inside accept for the nasty burned smell!! So I jacked the rear end up, and there is no play on each of the rear wheels. So I jack the front end up, there's a little rotational play in the front, but the bearings are ok (no play in them or the tie rods). Both driveshafts are good and the u joints appear ok too.


However, I found something. The Jeep has 225/70/15 tires all around accept on the right front when it has 235/70/15 tire on it!!! Could this have damaged the transfer case? Would this cause the front and rear diffs to REALLY heat up enough to make them smell?

SpooledupRacing

I really dont think it is the tire issue... I would now check the T-case... how low as the fluid in the diffs???

If you put it in 4L does it do the same??

91cavgt

The rear diff fluid level was fine, but the fluid was definately burnt. What else could have caused the diff fluid to burn, but no metal shavings were found in the diff? I'm willing to bet that the front diff fluid is burnt too with how hot the front diff was after the drive. Why don't you think the tire issue caused it? This morning I'm going out to check the front diff and the transfer case. At bare minimum I'm changing the fluid in both of the diffs and checking the fluid in the transfer case. I'll check it out in 4L to see if it makes noise too.

What else could it be? I was thinking the noise I was hearing was the TC chain hitting the case.

caged

gear oil has a nasty smell, even out of the bottle. so i'm thinking it's something else.

pull the wheels off and check the brakes.

91cavgt

When you can smell the diff fluid 30 feet away with the diff covers still in place, it is DEFINATELY burnt!! There was smoke coming from the rear diff when I parked it.

deschnei

I don't know about your Jeep but i had an Astro van that was all wheel drive and I made the mistake of putting a pair of different sized tires on the front end. I drove it about 20 miles before the rear end started smoking. I was told on any vehicle that is full time 4wd NEVER put different sized tires on front and rear. That little mistake cost me almost $3000 before I was through.

sems

I would check both differentials out (pull the cover and inspect). Put the proper size tire on would be my #1 thing, it can/will cause a lot of problems in the differentials and transfer case (especially with full time 4wd). Change the fluid in both differentials and check the transfer case fluid, slap the proper sized tire on and try it out...

91cavgt

I just got finished changing out the rear diff, front diff, and the transfer case fluids. Here is what I found;

Rear diff - Fluid was badly burnt, smelled worse than what diff fluid normally smells. I can't put the drain pan in the garage like normal because the smell gets into the house. You can litterally smell the burnt fluid 30 feet away! The gears looked perfectly fine and there was ZERO metal in the bottom of the diff and no shavings anywhere.

Transfer case - The fluid smelled a bit burned and was a dark red, so I changed it. There was ZERO metal/aluminum shavings.

Front diff - The fluid was so thick it was like molasses!! It was a bit burnt, but not nearly as bad as the rear diff. Once again, there were no shavings and the gears looked perfectly fine.


Tomorrow after work I am going to try to find a used tire of the right size. All else fails, I'll put a new tire on it and later down the road replace the other 3 tires.


I also checked the tire pressures. They were all REALLY low. Pressures ranged from 24 psi to as low as 16 psi!! This probably made the situation worse. All tires were reset to 30 psi.


After all this was done I drove it in town about 3 miles with the front driveshaft intact. There were no noises and it drove perfectly fine.

bigomudders

On a ALL WHEEL DRIVE the tires HAVE TO BE THE EXACT SAME SIZE or the transfer case can not keep the tires spinning at the same rate (hince causeing the rearends to get smoking hot) and you will damage the T/C