I got a 2000 xj I recently purchased with a chrysler rear end and I am getting a high pitched hum around 50 mph. I have had the rear end serviced and pinion bearings checked and no sign of major wear. Only thing I could figure was axle bearing or transfer case. Any input would be helpful.

P.s. new to the forum and jeeps!! Lovin em both so far!

 

Checked your u joints recently?

 

Nope.

 

1. Wear could still exist on rear gears to cause the noise.

2. Backlash on rear gears could be wrong.

3. Axle bearings could be going out.

4. Sometimes the noise will last for years and miles without anything major happening.

 

Ya I'm going to look at the bearings next. Thanks for the input

 

Are you having any vibrations with the humming noise? While your under the terms just check your u joints for play and if they haven't been replaced In a while it wouldn't hurt to do so. They are 10 bucks

 

I have the same problem. I've had my driveshaft rebalanced with new ujoints pinion seals and new fluid in the rear end still can't figure it out

 

Who worked on the rear end? The carrier clearances might be off

 

I'm having no vibration or performance issues just the annoying hum! Lol. But I'll check out the u joints

 

Ya I work in Chrysler parts so I had our mechanics look at it and they couldn't figure it out either. They ran it on the lift with a stethoscope to it and couldn't find the source. It only does it between 45 and 55 mph and is The highest pitch at 50, and is louder when accelerating then not. If that makes sense

 

Same here. My ujoints are brand new tho

 

sounds like a rear pinion bearing i just replaced my moms whole rear axle in her tahoe (was cheaper) for her

 

I had that on a 95 zj all wheel all the time. Turned out to be the part between the drive shaft ujoint and the diferential was worn out. Took it to a 4x4 center and fixed it. I can't remember what the piece was called though. ... bell housing maybe? I think thats it. Look up bell housing .

Yeah the pinion bearing was shot and the bell housing was shot. Changed the pinion bearing and had to get the bell housing from a junk yard.

 

Bell housing is between engine and transmission. Your pinion gear is inside the diff, riding in the pinion bearing and bolted to the pinion yoke. Pinion yoke attaches to u joint

 

"and is louder when accelerating then not."

Ring gear and pinion teeth are worn on the thrust side.