Rear end noise under acceleration…

[Nicksq30]

Alright guys first off I apologize if this has been addressed before, but I was unable to find it. I’m having a whole bunch of weird noises coming from the rear of my explorer under acceleration. Although it appears to be more frequent under “harder” accelerations it can make the noise under any. The searches Ive done come up with more people suffering from a ‘whine’, while this is more of a “chirp” or “squeek” sound. It sounds like a noise a belt would make, but is definitely coming from the rear. It is only under acceleration, the second I take my foot off the gas it stops, then returns when I accelerate again. The noise is also intermittent, and I cant find any pattern that its seems to follow.

I’m not sure where to begin searching… I admit its been snowy and cold and I haven’t gotten under there to look at all. I plan to enjoy a nice heated garage over winter break to try to find this, but was hoping for some guidance in where to start my search…

 

[BrooklynBay]

This is the first sign of the rear U joint starting to fail. Eventually it will start to bang, and will be more noticeable. It's the U joint closest to the differential. It will look fine, and even feel firm if you wiggle the driveshaft, but if you remove the U joint, you will see wear inside of it.

 

[964dexp]

what is the mileage on the truck? around 135k - 140k the rear pinion bearing likes to start showing wear. if you place the truck in reverse or drive does she clunk at all? you can have someone rock the truck back and forth and watch the pinion shaft for movement and noise. good luck, brian!

 

[Nicksq30]

Thanks for the help. The mileage on the truck is about 110k, so I figured Ujoints weren’t far off from need replacement even if this wasn’t my problem. Most U joints Ive seen fail though make more noise under a coast, rather then an acceleration.

Also I don’t really have any clunks when I shift it, but I plan to take a good look at the rear differential as well… I just hate chasing down noises!

 

[Nicksq30]

BrooklynBay you were 100% right. The U joint felt “slighty” worn; had only a very small amount of play in the driveshaft… But once I removed it I found NO needle-bearings left under one of the caps! The rest looked adequate… but I couldn’t believe all I was having was a noise and not some serious vibrations.

 

[BrooklynBay]

The same thing happened to me. I was also very surprised. Did you replace both U joints, or just the rear one?