When I first start my jeep in the mornings and start off sometimes it makes a sqealing sound from the rear of the vehicle. Just when I tap the gas once or twice it does it, then won't do it again until it sets and cools off for awhile. It does it when I start off in the morning, and then when I start to leave work and go to my 2nd job/school. Anyone know what this might be? Any help is appreciated. It just started doing it a few days ago.

 

Never had a squealing from the rear end of the Jeep. Does it sound the same as a slipping belt on the engine? Please try to further explain the sound and exactly when it happens ;ie: when the Jeep is in reverse or when the brake is being released or something more descriptive to help us to understand what it sounds like and when exactly you hear it.

 

Check your rear universal joint at the axle. I once had a u-joint that would squeal, when I took the driveshaft down it damn near fell apart. That or maybe rear brakes.

 

Brakes are not applied, only when I tap the gas on first startup. It sounds like it could be a belt, but it isn't coming from the front of the truck.

 

Rear engined Jeeps are very rare.
Try the U-joint as there are few moving parts further back that that.

 

Its probably your belt, it is very common. I would try replacing your belt or simply tightening it and see if the problem goes away. Even if the problem doesnt go away at least you have a new belt which is never a problem.

 

I don't think one could get confused as to where the sound was coming from if it was a belt squealing. I would disconnect the rear drive shaft from the diff and inspect. Might be a good idea to go ahead and pull the cover off the diff too and change the oil plus you can check for metal shavings and inspect for wear. Remove all lower bolts leave two in the top but loosen them. Separate the diff cover with a flat tip or what not. Fluid will come out. Grab a magnet and swirl it around the fluid. If it is covered in metal shavins may be time to get a new diff. Other wise at least you changed your fluid. Replace it with 2 quarts of Lucas 80/90

But it is probably the U-joint on the drive shaft

 

Does the noise only take place when while you're moving, or will it make the noise when you are not moving. If it does then it is not a u joint or anything in the rear of the XJ. Nothing is in motion back there if you are not moving, besides the fuel pump. How long has it been since it had a fuel pump put on it? That might be your problem. Good luck, hope this helps!!

 

May be a clutch pack in a LSD that is dry or low on friction modifier. Just occured to me. I guess I never thought about it b/c I have never heard one squeal.

 

Only happens when I'm starting off or moving slowly, never when I'm idling, or at a stop (park). It has a 2 week old gatorback serpentine belt on it since it was squealing from there when I got it. I will check the u joints and all tomorrow then. Thanks for the help.

 

Blue has a point. I did not think of that, try to find out if it has LSD. That could damn well be it!

 

Could also be something in the brake drums like broken spring or even rust.