Rear differential lube question

[bubbatrucklover]

I drained the oil and removed the rear differential cover on my 2002 Chevy 10 bolt rear end. This is the second time I am changing the oil in the 3 plus years I owned it but, the first time pulling the cover. I found a blob of nasty grease on the magnet. Is this synthetic gear lube or axle grease to help collect and retain shavings/chunks? If so what should I buy to replace it?

I noticed 4 small,small chunks of metal but, it has been re geared prior to owning it and I would think a few small chunks was semi normal.

Also I skimmed through Jarrod's rebuild thread and didn't see the blob of grease replaced. Is this just assembly grease that rolled off from the gears.

Thanks in advance.

 

[Black02Silverado]

It sounds more like you have a serious metal shaving build up on the magnet, super fine stuff that makes it seem like grease. That is the main purpose of the magnet to collect the ferrous metal and keep it from floating around since it is abrasive.

Depending on the way it was regeared if the clearances were off it could have more wear than normal. As long as you don't have any noise or other noticeable issues it sounds like all is ok. How many miles on the oil changes each time?

 

[bubbatrucklover]

The total mileage is little over 200,000. If I recall I think the PO said it had to be re geared twice to get the backlash or something right. I first drained the gear oil at about 160,000 (shortly after I got the truck). So now aprox. 40,000 miles later.

Hard saying if anyone bothered to clean the diff cover thoroughly since the factory. No noise or probs in 3 years that I can tell. My question is even though the lube and gasket is $50 ish it's still cheaper then a new rear end.

Should I redo this in another month or several thousand miles to check for the used oil and shavings or wait 'til the next scheduled change?

 

[ProZach]

The total mileage is little over 200,000. If I recall I think the PO said it had to be re geared twice to get the backlash or something right. I first drained the gear oil at about 160,000 (shortly after I got the truck). So now aprox. 40,000 miles later.

Hard saying if anyone bothered to clean the diff cover thoroughly since the factory. No noise or probs in 3 years that I can tell. My question is even though the lube and gasket is $50 ish it's still cheaper then a new rear end.

Should I redo this in another month or several thousand miles to check for the used oil and shavings or wait 'til the next scheduled change?

I would suggest doing it sooner than the next recommended, purely for ease of mind given that you can't be 100% sure whether or not the shavings are irregular or regular and the second change in the somewhat near future could help determine that.

 

[Black02Silverado]

For the cost of the fluid doing it sooner to inspect it would be wise. Some use a gasket on the cover and some just use RTV either way it isn't to bad a cost.

 

[bubbatrucklover]

I would suggest doing it sooner than the next recommended, purely for ease of mind given that you can't be 100% sure whether or not the shavings are irregular or regular and the second change in the somewhat near future could help determine that.

For the cost of the fluid doing it sooner to inspect it would be wise. Some use a gasket on the cover and some just use RTV either way it isn't to bad a cost.

That's what I was thinking and I have the gasket and the black RTV. I think together they're $10 plus the $45 for fluid. Like we said MUCH cheaper then a new rear end.

 

[Draenor]

When in doubt, you can always put marking compound on the gears and check the mesh pattern. The small fine metal is ok and is normal. Any big chunks are a concern. Its probably part of the G80 is you have it.

 

[bubbatrucklover]

Thanks John. I don't really know about marking compound. When I pull the cover in 1,000 miles (or in a month) if I see to much crap on the magnet I'll re consider what to do.

 

[Bigredmariner]

Yeah the "grease" you are seeing on the magnet is fine metal filings. Short of tearing the rear end down and doing a full setup, just give everything a good look over. Look at the ring gear and see if there is any spalling on the face. Spalling is when chunks of the face material start to pull away, instead of seeing a smooth surface it will have what looks like pitting. This usually happens when a gear is setup too tight.


Posted from my iPad via Tapatalk HD.

 

[bubbatrucklover]

Is this signs of the spalling you're talking about Jarrod?

If so what am I looking at to "loosen" it up (for lack of a better term)?