Rear 3.42 rebuild odd axle bearing wear

[West 1]

Damaged OEM bearings, axle shaft shows identical marks inside where bearings run

Second photo of damaged OEM bearings

I

Third photo is New Timken on Left, damaged OEM bearings showing the back un damaged side on right.


I am rebuilding the rear Differential on my 08 Denali. Main complaint is a rear axle whine while accelerating. I plan to install all new bearings, Pinion, Carrier and Axle along with a rear brake job as part of this repair.

Before tear down I was hoping my noise would be found to be a Pinion Bearing failing. I don't have them out yet but pulled both axles and the axle bearings. Found the Pass side had a seal leaking at the axle bearing.
Pulled both axle bearings and found the same odd marks on the outside of the bearings and in the axle tube, both on the TOP of the housing facing the roof of the car????

I worked for a bearing manufacturer for 30 years, saw lots of bearing failures and normal wear bearings over the years. Have never run across this type bearing damage.

I took a couple pictures of the old bearings showing the wear and the opposite side showing they look perfect. All the rollers show no wear I have found?

The new bearings came in, Timken, still Made in the USA. I was shocked thought for sure they would be China made.

My only guesses would be that someone Welded on this vehicle while these bearings were in the car and the weld grounded through the bearings? If it was from going over a hard bump while driving I would expect differing damage side to side?

I will pull the pinion bearings out for inspection next then the carrier bearings, I have new replacements ready to go.

The last thing I am worried about is the Ring and Pinion gears. I am concerned they may have been damaged due to the leaking axle seal lowing the oil level? Noise on Tip in is normally gear noise not bearing noise? My noise did not change in pitch while turning left or right and goes away when you let off the throttle. I have ordered a new Ring and Pinion set so I will be prepared if that is needed. At this point I am wondering if I should have purchased a complete axle assembly to drop in.

Curous what you guys have seen in the past.

 

[strutaeng]

Yikes!

What does the housing where the bearing go in look like? Almost look there's a defect on the housing and the bearing tried to spin?

Are those chatter marks? It's hard to tell.

View attachment 462669
Damaged OEM bearings, axle shaft shows identical marks inside where bearings run
View attachment 462670
Second photo of damaged OEM bearings
View attachment 462671I

Third photo is New Timken on Left, damaged OEM bearings showing the back un damaged side on right.


I am rebuilding the rear Differential on my 08 Denali. Main complaint is a rear axle whine while accelerating. I plan to install all new bearings, Pinion, Carrier and Axle along with a rear brake job as part of this repair.

Before tear down I was hoping my noise would be found to be a Pinion Bearing failing. I don't have them out yet but pulled both axles and the axle bearings. Found the Pass side had a seal leaking at the axle bearing.
Pulled both axle bearings and found the same odd marks on the outside of the bearings and in the axle tube, both on the TOP of the housing facing the roof of the car????

I worked for a bearing manufacturer for 30 years, saw lots of bearing failures and normal wear bearings over the years. Have never run across this type bearing damage.

I took a couple pictures of the old bearings showing the wear and the opposite side showing they look perfect. All the rollers show no wear I have found?

The new bearings came in, Timken, still Made in the USA. I was shocked thought for sure they would be China made.

My only guesses would be that someone Welded on this vehicle while these bearings were in the car and the weld grounded through the bearings? If it was from going over a hard bump while driving I would expect differing damage side to side?

I will pull the pinion bearings out for inspection next then the carrier bearings, I have new replacements ready to go.

The last think I am worried about is the Ring and Pinion gears. I am concerned they may have been damaged due to the leaking axle seal lowing the oil level? Noise on Tip in is normally gear noise not bearing noise? My noise did not change in pitch while turning left or right and goes away when you let off the throttle. I have ordered a new Ring and Pinion set so I will be prepared if that is needed. At this point I am wondering if I should have purchased a complete axle assembly to drop in.

Curous what you guys have seen in the past.

 

[West 1]

Housing on both sides show identical damage to the bearings, this is what has me thinking someone welded on this rig at some time. I am a short time owner, bought it at 145,000 miles with a broken engine which I repaired. I am going through the truck trying to repair anything it needs.

The Bearings show no chatter marks, all rollers are smooth that I have seen so far. I will look harder. The pinion bearings spin smoothly but are still in the diff.

 

[SpareParts]

Odd for sure.
I would think if it was from welding the damage would be on the inner bearings and axle. The outer bearing race has to good of a contact patch to arc.
Maybe getting hot from low lube or over weight on the top where the weight is carried and the bottom would stay cooler? Would be my best guess.

 

[West 1]

Timken shows a bearing analysis poster, it shows one bearing with similar wear or damage, says it is over loaded damage. Maybe they are correct,

 

[swathdiver]

Is this an AWD or RWD 2008 Yukon Denali?

Post up pictures of the inside of the tube where the bearings go and the ring and pinion when you pull all that apart. I overhauled one last year.

You can have my old 8.6, it's still sitting on my driveway and works just fine.

Timken and Koyo bearings were used in these and really, there's none better. I have found that buying the kits from AAM, the axle manufacturer, saves quite a bit of money.

 

[West 1]

It is an AWD Denali with the 6.2L. I have a complete Rebuild kit here, bearings and seals plus a variety of shims from prior jobs.
Thanks for the very generous offer, looks like you are in Florida I am 3,000 miles away. Freight takes me out of that possible easy fix.

I have a replacement ring and pinion coming but I can't visually eee any wear in my existing ring and pinion. I will pull it shortly and examine the bearings closely.
Even though the axle bearings show a damaged outer case they seem to spin free and the rollers show no damage or wear so I don't think they are the noise issue.

Pictures of the axle tube before I cleaned it up.

 

[West 1]

 

[West 1]

The sad part about this situation, I had a complete 3.42 rear axle, brake to brake in my garage that was in the way. I sold it about 2 years ago for $200, it was an open diff unit with no posi so demand for it was very low. My truck had 3.73 gears so I let it go. Wish it was still sitting here I could have mixed and matched it with the Denali diff and made one good Diff for almost nothing. Hind sight is always perfect.

 

[swathdiver]

Do you think the bearing spun in the tube? How are the ABS reluctors? Any damage when you pulled the bearings?

How are the axle shafts where the bearings ride?

Mine had some wear and instead of cleaning them up, just replaced them with new.

 

[strutaeng]

Overload? Interesting. I guess that makes sense. On a SUV it seems less likely, no? Do you know if they towed with it?

If it was a truck, maybe more likely? I once went to the gravel place and got a full yard of sand on my 99 Silverado. I was inside the cab, and didn't realize the rear was basically bottomed out until I got home. I spent like the rest of the day shoveling/wheelbarrowing sand off the bed, LOL. I didn't realize it then, but 1 yard of wet sand weighs about 2600 lbs. Oopsie.

 

[OBSandaNNBS]

6

Yikes!

What does the housing where the bearing go in look like? Almost look there's a defect on the housing and the bearing tried to spin?

Are those chatter marks? It's hard to tell.

I was initially thinking this too, but the overload theory is making sense to me, esp because it's on both sides, same place.
I wonder how long they've been like that.

 

[Doubeleive]

I had a similar issue before. I came to conclusion that it must be the axle housing worn, albeit it had 320k on it as well.
I ended up selling it and I know it went to a shop I sometimes use after it sold for leaking axle seals....., I probably did them 5 times, new bearings, new seals, new axles as well,
supposedly there is sleeve kit but never looked into it before i sold it.

 

[mikez71]

I wonder what the inside looks like.. (Cut the bearing open!)

 

[West 1]

No damage from pulling, I used a puller that did not touch the axle housing. Axles are clean and measure straight. Zero sign of the bearing spinning on the shaft or in the housing.

I have rotated the bearings and inspected all rollers under a magnifier. All look perfect. I really think my noise was in the Pinion or pinion bearings.

Maybe the owner decided to jump this thing and landed it hard or banged a speed pump at high speed causing the damage?

 

[j91z28d1]

while odd, being on the outside of the race, I don't think this will effect anything if the axle rollers and race look good where the rollers roll. no metal anywhere.

if new bearings install smoothly, if it was mine I'd sent it. if on the test drive it didn't make any noise. I wouldn't give it a 2nd thought.

 

[strutaeng]

Maybe just sand off any ridges on the housing (with a small sanding block registering on the flat, good surfaces so as not to introduce undulations), and install new bearing with that Loctite sleeve compound? I believe there's different formulas, but they are designed for filling in small gaps in sleeves. I've used it for the long sleeve/bushing on the center supports of the few 4L80e transmissions I've rebuilt. All it takes is a very thin layer.

I think I used the 740, but it's something like this: https://next.henkel-adhesives.com/u...tral-pdp.html/loctite-680/BP000000153464.html

https://datasheets.tdx.henkel.com/LOCTITE-680-en_GL.pdf

Will probably require some heat to remove them though next time? IDK if that's a good idea now?

 

[West 1]

The pinion bearing are now out and removed. They do show wear but no damage, what I would expect at 145,000 miles. I am still thinking my whine may be in the ring and pinion gears.

 

[strutaeng]

The pinion bearing are now out and removed. They do show wear but no damage, what I would expect at 145,000 miles. I am still thinking my whine may be in the ring and pinion gears.

Did you happen to check for backlash prior to taking them out?

 

[West 1]

I thought of that after I already removed the pinion nut so I did not measure the backlash. It was excessive as I could hear it clank sometimes.