Driveline Noise - Help!!!

[stino]

Hey all, someone in our crew's Jeep started humming around 25-30mph+. They originally thought it was a tire issue, it changes with speed. Put it up on jackstands and ran it in drive and reverse - same results.

See the video:

He has aftermarket gears 5.13s, with probably about 5k miles on them. The Jeep as a whole with 12k. Any ideas? Driveshaft, diff, something else?

Thanks!

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[word302]

Hey all, someone in our crew's Jeep started humming around 25-30mph+. They originally thought it was a tire issue, it changes with speed. Put it up on jackstands and ran it in drive and reverse - same results. See the attached video:

He has aftermarket gears 5.13s, with probably about 15k miles on them. The Jeep as a whole with 25k. Any ideas? Driveshaft, diff, something else?

Thanks!
View attachment 623738

I would almost be willing to bet it’s the dual-row pinion tail bearing. If whoever did the gears didn’t get the preload just right they probably toasted it.

 

[chevymitchell]

I would almost be willing to bet it’s the dual-row pinion tail bearing. If whoever did the gears didn’t get the preload just right they probably toasted it.

I would agree with this. This sounds like a bearing that was loaded much too high and it's burned up.

Rebuild the diff with a fresh set of bearings and it'll go away. While in the process of doing so, go through the entire diff and make sure it was put together right. Before removing the diff, get a picture of the pattern and measure the total TQ to rotate. This measurement with the axle shafts out will tell you immediately if the bearings are burned up.

 

[stino]

Thanks guy, shop that installed the gears is pointing to the driveshaft from the video.

 

[chevymitchell]

Thanks guy, shop that installed the gears is pointing to the driveshaft from the video.

It's certainly possible. You can take the driveshaft off and inspect the backside of the rzeppa joint. I've seen this punctured a ton of times from people trying to use a flat head to remove it from the flange. Once it's punctured, then the joint is exposed to the elements.

However, this does not sound like a failed rzeppa joint. I'd remove the driveshaft, leave it on jack stands, and just turn the wheels or pinion by hand. See if you can feel anything dragging or grinding.

 

[word302]

I would agree with this. This sounds like a bearing that was loaded much too high and it's burned up.

Rebuild the diff with a fresh set of bearings and it'll go away. While in the process of doing so, go through the entire diff and make sure it was put together right. Before removing the diff, get a picture of the pattern and measure the total TQ to rotate. This measurement with the axle shafts out will tell you immediately if the bearings are burned up.

Sadly this makes me wonder what else they screwed up. It seems that setting up gears is a dying art. Another reason to just do them yourself unless you really know somebody that knows what they’re doing. He’ll even that isn’t a guarantee these days, just ask @Some Random Guy

 

[chevymitchell]

Sadly this makes me wonder what else they screwed up. It seems that setting up gears is a dying art. Another reason to just do them yourself unless you really know somebody that knows what they’re doing. He’ll even that isn’t a guarantee these days, just ask @Some Random Guy

Everyone that knows how to do them right has screwed them up. Lol. I've screwed up my share, I promise you that, but it's a learn from mistakes environment and move on. It's a good thing they're adjustable and it's very hard to screw them up once you have the experience. It's just the waiting on parts thing that sucks after that.

 

[Some Random Guy]

I screwed my own up the first time! But then we got it right.
Maybe it’s just an accountability issue in today’s society. Nobody can admit they were wrong without a lawyer rubbing their hands and drooling.

 

[stino]

Thanks everyone! Was able to rule out the driveshaft thanks to the suggestions in this thread.

This is a major 4x4 shop in the LA area, that I have to imagine has has done 1000s of these at this point. They’ve been super responsive and are taking a look at it next week. Shit happens, I spose, really matters how they handle it from here

 

[roaniecowpony]

You might be able to detect a pinion bearing problem by just taking the driveshaft off and hand turning the yoke and feeling for backlash and lateral bearing movement.

 

[Some Random Guy]

Thanks everyone! Was able to rule out the driveshaft thanks to the suggestions in this thread.

This is a major 4x4 shop in the LA area, that I have to imagine has has done 1000s of these at this point. They’ve been super responsive and are taking a look at it next week. Shit happens, I spose, really matters how they handle it from here

Good luck! Big shop didn’t help me, but I eventually got refunded after bringing in the parts they installed with crazy wear patterns.

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