pinion bearing or U-joint?

[Hubnut]

I get a wierd noise (maybe some vibration but not much really) from my rear end when I let off the gas after accelerating. Hard to describe the sound, sort of like when you wander into the median where they've cut those grooves to wake you up. Drive shaft and ujoints are only 6 months old. 14 bolt rear end with locker from a CUCV (m1008) with 4.56 gears. Also, it is happening more frequently now, but sometimes it doesn't do it. Gear oil is fine. I pulled the cover and the teeth are fine on the ring gear and pinion (far as i could see). Sound is definitely from the back end. Thanks for any input.

 

[Hogback Fabrication]

Put the truck in neutral and chock the tires. Grab the driveshaft and move it back and forth. If the pinion yoke has any in/out or side/side play its the pinion bearings. If the u-joint has some slop in it that's the problem.

 

[ct85k10]

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I have the same noise. Ujoints are good and i had the rear end apart to put the lockright in and all the bearings felt good. the only problem i could see was a slight groove where the 3rd bearing rides on the the pinion. Changing the gear oil will quiet it for a little while but it comes back

 

[Hogback Fabrication]

subscribed
I have the same noise. Ujoints are good and i had the rear end apart to put the lockright in and all the bearings felt good. the only problem i could see was a slight groove where the 3rd bearing rides on the the pinion. Changing the gear oil will quiet it for a little while but it comes back

Try to see if there is any play in the pinion yoke