Front diff, spun carrier bearing

[Thealmightyphil]

Good morning All.

Just wanted to share some interesting findings, did a quick search but couldn't see anything on this previously (probably user error).

I've had my HDJ80 for somewhere between 1-2 years now and the whole time I've owned it the original front (locking) diff has been whining. Not a problem I thought, ill get that off and rebuilt in due time (there were bigger mechanical fish to fry first [nearly had a BEB failure, see my previous post]).

Well the whining had been getting worse, it really started going at 50mph until around 70mph, to a point it was driving me crazy.
So as other jobs were now due at the garage (my neighbor reversed into front of the 80 and took out many pretty parts and the A/C dryer) I thought id also finally get that front Diff rebuilt, at this point assuming the issue was pinion preload and gear alignment...

Well would you look at that:

Well! Looks like we now know what the whining was, it was a spun bearing! The carrier housing was spinning inside one of the carrier bearing! The mechanic said while the bearing was still in a "tight" fit, it was more of a transition fit than interference fit, as prying with a screwdriver was enough to get the bearing off the housing. (he also cheekily told me at least the bearing looks in really good condition... yeah no s*** it hasn't been spinning!). He also remarked there was an excessive amount of backlash in the diff, so a tear down was long overdue.

Now gentlemen onto the fix... or more accurately I should I say bodge.
For my region as were now into the territory of a "new" refurbished diff imported from overseas, and add that to some logistic issues meaning we need to get this 80 back on the road asap, we took the less favorable option. The peen and tack! (well need a new diff anyway, what have we got to lose)

I don't have any photos from this part, but the carrier "shaft" has been peened to increase interference fit and when the new bearing race had been pushed into place with a press it was very lightly tacked to ensure the race was going to be stationary this time (against the carrier housing). Then after that we were back into normal rebuild territory, new bearings, new solid (non-crush) preload spacer, preloads set, gears painted and alignments set.

So gentlemen, I just wanted to share with you an interesting finding.
I will let you know how long the peen and tacked front diff lasts. I don't expect it to last forever but will report back when it fails, and by that point ill have saved up to buy a refurbished front diff anyway.

Phil

Edit: The whine was only present under load (foot on the accelerator), any coasting or braking would silence the noise, accelerating or maintaining speed with the accelerator would be met with the constant whine.

 

[Rusty Marlin]

that's different. thank you for sharing

 

[use2bn83]

I’ve seen this a few times. I’ve peened and added green sleeve retainer compound at least 3 times, but have never tacked one. I’m sure that will work just fine. I have one in my truck that is 40k miles in that was peened and sleeve retained, no issues yet and it gets flogged pretty hard.

Not uncommon to remove the big bearing side with 2 opposing pry bars and a little wiggle.

 

[Thealmightyphil]

I’ve seen this a few times. I’ve peened and added green sleeve retainer compound at least 3 times, but have never tacked one. I’m sure that will work just fine. I have one in my truck that is 40k miles in that was peened and sleeve retained, no issues yet and it gets flogged pretty hard.

Not uncommon to remove the big bearing side with 2 opposing pry bars and a little wiggle.

Thanks for sharing. That's good to know, I wasn't sure how common this was.

In my opinion, so long as the bearing isn't so loose you'll have runout then this is a reasonable fix given the alternative is essentially a new diff. Likewise with the tack welding, so long as its light enough to not distort the shape of the race, we should be fine. Just need the bearing to run WITH the "shaft" not over it.

Extra bit of info: My cousin who is a truck fleet mechanic says this is a very common issue and fix in his line of work.

 

[Bigtoepfer]

I have a whine in my rear diff. And I'm afraid this is the issue.
I've just been politely ignoring it as best I can. 2500 mile round trip to Colorado earlier this month was issue free and it doesn't seem to effect fuel mileage. Did my axle bearings in the rear thinking it might have been one of them, and they were over due anyway. Sound didn't go away of course. Not excited to pull the whole thing apart.

 

[Thealmightyphil]

I have a whine in my rear diff. And I'm afraid this is the issue.
I've just been politely ignoring it as best I can. 2500 mile round trip to Colorado earlier this month was issue free and it doesn't seem to effect fuel mileage. Did my axle bearings in the rear thinking it might have been one of them, and they were over due anyway. Sound didn't go away of course. Not excited to pull the whole thing apart.

Im not the expert on the subject, but I have been told by the more experienced that its usually the diff if the whine is only present when "under load" ie. foot on the gas, if you lift off the accelerator and the whine goes away, its most likely something going on with your diff (pinion preload/gear alignment/diff bearings etc)

One other easy thing to check though, make sure those UJ's are full of grease!
Get a dose of grease to all the grease nipples on the UJ's and drive shafts. Might save you a headache, also might yield disappointment if it does nothing! Goodluck!

 

[Bigtoepfer]

Yea I did the drive shafts a couple of times between the last oil changes, just to be sure. I've systematically ruled out just about everything and I'm down to output of transfer case, pinion, or something inside the diff.

Like you said, only under load.

 

[Thealmightyphil]

Yea I did the drive shafts a couple of times between the last oil changes, just to be sure. I've systematically ruled out just about everything and I'm down to output of transfer case, pinion, or something inside the diff.

Like you said, only under load.

Its never the easier options is it...
Unfortunately sounds like a diff pull may be in your near future, probably better to grit your teeth and get it done sooner rather than later (says the man who put ~10k miles on a whiny diff for nearly 2 years).

 

[Bigtoepfer]

I've got about 17k since I bought it just over two years ago. I didn't notice the whine until took the MTs off and put the new tires on that were silent on the highway.

I'm just hoping only the diff is affected and not the whole rear end. And it's a little outside my wheel house so I need to find someone reliable to be able to do this for me.

 

[Thealmightyphil]

I've got about 17k since I bought it just over two years ago. I didn't notice the whine until took the MTs off and put the new tires on that were silent on the highway.

I'm just hoping only the diff is affected and not the whole rear end. And it's a little outside my wheel house so I need to find someone reliable to be able to do this for me.

Sounds like its time, I would be surprised if it were anything worse than what I've found, I would have thought if the diff had truly s*** the bed then the noise would be far more than just a whine.

And the work to fix the spun bearing was minimal compared to the overall diff rebuild job, only cost me an extra hour in labour. I'm sure you'll be able to find a diff rebuild shop you can mail it off to, who knows maybe buying a reconditioned one would be cheaper.

 

[PIP]

Spun differential bearings are commonplace. It's a symptom of inadequate carrier preload combined with heavy load. 99 times out of 100 its the ring gear side bearing, just like in this case. With enough carrier preload this will never happen. So basically, if the bearings looked good when you took it apart it was assembled wrong to begin with.

I'm not a fan of tack welding bearings. Lots of reasons it's not the greatest idea.

Dimpling the carrier surface and installing the bearing with green loctite is how most diff shops do it.

Another way is to turn it down a little and nickel or chrome plate build up then grind to size. There is also metal spray build up, but I'm not the biggest fan of that for bearing fits in heavy load situations.

Looks good! Glad you found your whine!

 

[tmxmotorsports]

This same thing was wrong in my cousins tough truck jeep Dana 30 ring gear side bearing spun as @PIP Stated not enough carrier preload with a load its driven extremely hard along with jumping 10ft in the air to a hard landing. I just got him to grab another carrier dime a dozen used i set everything back up tight if the carrier comes out without much effort its not tight enough. If ya don't know what a tough truck is check out you tube Dennis Anderson muddy motorsports park tough truck videos.

 

[Thealmightyphil]

Spun differential bearings are commonplace. It's a symptom of inadequate carrier preload combined with heavy load. 99 times out of 100 its the ring gear side bearing, just like in this case. With enough carrier preload this will never happen. So basically, if the bearings looked good when you took it apart it was assembled wrong to begin with.

I'm not a fan of tack welding bearings. Lots of reasons it's not the greatest idea.

Dimpling the carrier surface and installing the bearing with green loctite is how most diff shops do it.

Another way is to turn it down a little and nickel or chrome plate build up then grind to size. There is also metal spray build up, but I'm not the biggest fan of that for bearing fits in heavy load situations.

Looks good! Glad you found your whine!

Good to know its not all that uncommon.

On the improper installation, an unfortunately common theme with this 80, seems to have been some mechanical incompetence/laziness from whoever worked on this cruiser in the past I've found many disappointing "repairs" as I work through the vehicle.

I'm not experienced on the matter in the slightest, before speaking here I wouldn't have thought peening and loctiting was even a suitable option, good to know for the future. Also interesting with the metal spray buildup, not something I've come across before.

This diff rebuild shop came recommended so lets hope they know what they're doing with the welding and pre-loads. My preference would have been to turn down the "shaft" to fit a smaller ID bearing, but that would have been financially un-economic not to mention I've done no research into other suitable bearing sizes.

Thanks! That whine was doing. my. nut.