Rear Differential Oil Change leads to.........w/ Pics

[Dutch02LTZ]

Hi,

I need some advice from others that have experienced this or similar, and if anyone has found the root cause.

I believe I have found the cause but need confirmation if my theory is correct.

This 02 of ours has low mileage for its age and only now has 176 km's with a rebuilt engine and trans under extended warranty by dealer. Then it was parked for a couple years, then given to us (wife and I).
I have done a lot of repairs on it and preventative/restoration.

About a week ago I decided to inspect and change the Rear Differential oil.
I don't know if it was ever done by the dealer, while previous owner (Father in law) had it under extended warranty.


When I pulled the drain plug I hear clink, clink, clink as the oil was draining into my metal oil catch pan.
I start fishing around in the oil to find metal teeth chippings, about 10 of them.

I open the Rear Differential cover to find this.
This is after removing the carrier and cleaning it with brake clean.

Top and bottom spiders are chipping teeth, sides look ok.

So I was thinking of doing a diff rebuild but after inspecting further this is what else I found.

Carrier Bearing Races were spinning under the caps. Notice the scoring and it actually machined out the aluminum housing and cap, no more tight fit.
Also notice there is a line down the axle tube. Looks like the axle has been moving in the tube and rubbing.

Other side, looks like axle indent from rubbing.

Outer Bearing looks, feels and sounds ok, never saw any signs of seepage even though the seal looks like crap.

So what I decided to do is get a new axle from a wrecker via car-part.com and my local wrecker.
I dropped a little more ($450 CAD) and got one on order from a 2005 with 70k on it.
I plan on just dropping out the old one and bolting in the new axle (after inspecting under the cover).

So I have been trying to figure out the root causes of:

1) The spider teeth chipping
2) The carrier bearing races spinning
3) The axle tube markings

So what I am thinking happened is this...


The only suspension parts that I have not changed on this vehicle since owning it are the Rear upper & lower trailing arms/control arms.
I believe that the bushings in these are worn (along with maybe the axle bearings) allowing the axle shaft to shift from front to rear of the vehicle (twist) which caused the markings on the tubes.

If the axle did shift back and forth this would put pressure on carrier bearings and the axle spider gears causing misalignment and chipping teeth.

Is my conclusion correct??
Are the rear control arm/trailing arms are the only thing that stop the axle from moving front to back/twisting?

Anyone else ever seen this?


Any suggestions or input welcome
Thanks in advance
Dutch

 

[Mounce]

I don't think the axles actually have that much slop, if any at all, that would make them that sensitive to bushings going bad. If they had slop like that the off road guys would be going through one a year with the abuse they usually put the whole vehicle through, that or the other normal drivers would also be reporting cases like this and I haven't personally seen one here like yours. I would lean more towards a defective unit first, then lack of maintenance second.

 

[Mooseman]

Aw man, although a bit away, I have (had) two I could have sold you.. Just a matter of getting it to you from Ottawa.

The differential carrier is self contained so even if shocks and or axle suspension arms were worn, it doesn't affect the internals. Unless there was a massive shock via the drive shaft or from the wheels, I suspect more it was lack of maintenance.

At the point you were in damaged parts, you are ahead by replacing the whole carrier. You won't even need to disconnect the brake calipers. Just unbolt and suspend them with bungees.

 

[Sparky]

I agree. And it may be an early model issue also as I had issues on my 02 rear axle.

I never took the cover off mine, but the original axle from my 2002 had a lot of metal in the gear oil when I changed it with 120k miles not long after I bought it. It also had a lot of slop in the gears. Surprisingly it was still quiet for a long while, but one day it started howling like a banshee so I did the same with a used axle from a newer truck (I upgraded to an 8.6" while I was at it).

 

[Mooseman]

Yeah, the 8.0 gears tended to self destruct easily. Back then, only the EXT and 5.3 would get the bigger gears.

 

[Dutch02LTZ]

Thanks for the responses.

The vehicle was neglected before we got it.
Previous owners (In laws) were the type that would wait until it was almost non drive-able before taking it in for service or repairs.
If the extended did not cover it they would just throw a pile of money at it & hope the dealer did not rip them off.
They also used to tow a boat with it & drive the crap out of it.

Since we got it we have sank a bunch of money (in parts) into it little by little repairing & restoring her.

I am guessing from what I experienced with them (dealer) they never changed the Diff fluid.
They were probably to busy doing the recalls, repairs & replacing the engine and trans.

Funny thing about the Diff is it was quiet and so were the bearings.
Fluid was full but very dark when I drained it.

Axle shafts did not have any excessive signs of wear on them and the splines looked good.
The only strange thing I saw was that the passengers side did not have much oil on it.

So you guys think it was inner and outer bearing wear that caused the axle shafts to shift/twist?

Also is the Diff supposed to have a magnet inside to catch shavings like the Trans?

Would like to try and prevent this from happening again with the replacement.

Thanks again

 

[Sparky]

Could have been anything. Honestly, the replacement axle is fine and you'll likely not have any issues with it. It sounds very much like how mine was, oddly quiet given the wear it had.

I don't think there was any axle shaft twisting. You already stated that the shafts themselves look fine. If they had been rubbing on the tubes you would have seen signs of that on the shafts. There would have had to be an enormous amount of flexing to get the shaft to contact the tube as they don't run that close to the tube walls.

Bolt up the replacement with fresh oil and call it a day

 

[Mooseman]

Also is the Diff supposed to have a magnet inside to catch shavings like the Trans?

Yes, very normal. You would usually just find some black iron sludge, just like in the tranny. If you see chunks, it's not good.

 

[Mounce]

Magnet is usually located on the cover. Unless it's built in to the drain plug that most of us don't actually have.

 

[Mooseman]

I think my 02 had both.

 

[Dutch02LTZ]

Thanks for the replies.
I will post back in a little while when I get her back together.

Dutch