Vibration in Rear End After Lift (1 Viewer)

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Joined
Jan 21, 2022
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Location
Albany, Oregon
So completed the 2" OME lift the other day and now notice a vibration in the read end at 50-55 mph. Suttle, but it is there. Went under the rig today and yanked and pulled on the drive shaft to see if there was any play in the U Joints. Nothing moving in the U Joint that I could tell, but was getting some movement out of what I would call the differential flange (#31).

Spoke with a guy who said it could be the differential nut (#33?) is loose allowing there to be some side to side play in that flange where it meets the diff.

So I am talking about 31 having some lateral (non-rotational) play in it. And he is telling me 33 might be loose and need retorqued.

Does this seem possible or a likely culprit. I am not sure what else would be causing a vibration back there that would only show up after the left went in.




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No experience with that nut yet, but when I first got my rig it would vibrate over 35mph. I was under there one day and noticed only 2 bolts in my drive shaft flange and one was loose. Its amazing it was not making alot more racket.
 
The flange (33 in your picture) should have absolutely zero lateral slop in it. It should be as tight as a…..

Increasing the angle of the driveshaft by installing taller springs makes the ujoints articulate more. If the driveshaft is a bit out of balance, there will be more vibration.
 
Old parts wear in at a certain angle and get comfortable living there. Adding 2” of lift changes that angle and you’re now not comfortable like you once were. Drop the drive shaft and check the differential pinion and transfer case output flange for play or slop. You may have had a problem before the lift and it’s only showing itself now that you changed things so drastically.
 
any metal in your diff fluid?

i had a similar problem when i did mine but it was because i used slightly longer shackles than what comes with an OME kit. check your pinion flange in comparison to the output of the transfer case. if they are not parallel you may need a castor shim to make them parallel. otherwise the u joints turn at a slightly different speed (angular rotation) and will cause a vibration. that being said there really shouldn’t be any play at the pinion so you may have that problem too
 
i know it’s a big job (because i’ve done it) but if your pinion bearing is worn you could pull the diff and swap it to the front as it’ll get a lot less use up there (unless you 4x4 a lot) and your gently used front one will now become your mail drive gears. otherwise i know @cruiseroutfit does a beautiful drop in diff build and the turn around is really quick. you could just get it rebuilt if it’s that bad.

i still would bet that it’s just a pinion angle thing though as it showed up only once the lift went in. that’s where i’d start anyway
 
i know it’s a big job (because i’ve done it) but if your pinion bearing is worn you could pull the diff and swap it to the front as it’ll get a lot less use up there (unless you 4x4 a lot) and your gently used front one will now become your mail drive gears. otherwise i know @cruiseroutfit does a beautiful drop in diff build and the turn around is really quick. you could just get it rebuilt if it’s that bad.

i still would bet that it’s just a pinion angle thing though as it showed up only once the lift went in. that’s where i’d start anyway
For the cost of buying pre built diffs from cruiseroutfitters it’s a no brainer. Buy two. Swap the diffs in an afternoon. Ship the cores back to CO. Easy peasy done deal with no hassle.
 

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