I have this noise in my rear of my XJ that is very pronounced and only happens under load that just started recently. It gets louder as I go faster, it is very loud. It only happens when I am on the throttle, as soon as I let off, the noise stops.

I thought that the noise might be water in my rear diff cause I recently got the rear stuck in a mud puddle overnight. I changed my diff fluid last night and the wrrrrrrr noise is still there. No metal flakes, chips or pieces.

Any ideas on what it could be? Maybe water in my axles?

For any that might know this sound, it sounds like dog cut gears in racing transmissions.

Any advice is appreciated!

 

I had a similar noise under load. I have a front cherokee driveshaft for my rear shaft, so it has a Double Cardan joint. Mine was dry of lube and squeeking. Check your ujoints and if you have the same driveshaft, check that too.

 

interesting...

I have stock rear driveshaft still, didn't change anything. Now after getting stuck in the mud for a night I have this noise that was not there before.

I did replace my front driveshaft as that is what broke and got me stuck in the mud, but I replaced it with a front from a donor cherokee at the junk yard.

The noise is definitely coming from the rear though.

Other suggestions?

 

You said you got stuck in a mud puddle? You probably have mud in your rear brake drums. Pull your tires off, remove the drums and clean it all out. That's what I'd check.

 

Thanks! I will do this but doubt that is what is causing this very loud wrrring noise!

 

A buddy thinks that the backlash may have come out of spec in the rear diff....what do you all think?

 

HELP!!

 

It could be you rear bearings.

 

^ most likely the cause since he got it stuck and soaked it in a puddle overnight how many miles is on your jeep? Have you ever regeared it. Sounds like that IMO

 

I have heard this when a ring gear was cracked. I only noticed this by removing the rear differential cover, jacking the rear end up and spinning the tire slowly. Not saying that this is the problem, but it sounds familiar.

 

never regeared, jeep is an 1989 with 106K mles.

sux, I just changed the diff oil, now I gotta pull it off again and check the ring gear.

 

It may be the bearings. A roaring noise is generally bearings, a whine comes from gears. If the gear backlash was set up wrong somehow it would make noise coasting and under load, so most likely not that

 

Are you the original owner? Has the Jeep been used aggressively off road?

 

If it happens only on acceleration, might be your pinion bearings.

 

definatly a backlash issue. adjust it before you destroy the rear end. excessive backlash causes only a small surface area of the pinion to contact the ring gear which means your risking breaking the teeth off.

not trying to scare you, but trying to let you know what might happen if you let it go too long and cause more trouble down the road