8.75 diff - metal in oil (pictures). Is it ruined?

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Keep the caps and adjusters oriented to their current sides of the unit.
I always clip a magnet inside a diff when I have one open. There's always a lump of iron/metalic goo on the magnet upon reopening of the axle.
But the amount of metalparticles in your diff are way too much. Something is wearing down fast.

Before you take it apart entirely, try to measure the gear's play or backlash as it's called.
 
I agree, I went to someone respected in the UK for building pro mod cars, with his own 5 second car.
Build a lot of UK top race vehicles, he inspected it and suggested the metal flakes might be from the shortened rear axle...

... The person that shortend the rear axle advises this is not possible as it was cut in a special way, with a water jet directing metal away from the casing...

I think the sure grip is not ruined but nearly ruined.

I don't mind taking it to bits, I just to not want to have a box of bolts and cogs I can't do anything with having lost all the pre-load settings etc. If I can take this to bits without causing a rebuild issue then fine!
 
If it's a 489 unit, you most likely have a crush sleeve on the pinion, and yes you will loose the preload on the pinion bearings if you take that out too.
 
So if I take out the main caps, 4 bolts, and makes sure they go back the correct way - nothing of the preloads/settings will be lost?
 
The only thing affected will be the backlash of the large gear. But that's easily re-adjusted with the side-adjusters.

If the diff-unit still rotates and feels nice and smooth, you could take a chance by cleaning everything out, flush the axle tubes thoroughly, assemble everything and drive around for a while before checking again later on.
Find a old computer harddrive, rip it apart and clip the strong magnet from it somewhere in the housing, just below the oillevel/axle tubes-level.
 
With junk in the bearings, the preload measurement will not be accurate, and probably not the backlash either.
As said above mark at least one cap. I do this by center punching the cap and case adjacent to each other, about 3/8 inch on either side of the parting line. If you mix them up, they will often not take the adjusters back in. Exactly where the marks go is not important. What is important is that at least one side is so marked.
Don't worry too much about putting it back together; there are several guys here that can help you through the reassy.
If you find that you have a Trac-Loc, Check down in the holes where the axles go, and make sure the thrust-buttons are still in there;one on each side.
Also check your axle bearings, and inner seals.
 
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I agree with that.
Best case scenario would be the guy who narrowed the housing didn't flush if out properly and it's still left over from the cutting.
Even if it was done with a watercutter, the metal being cut had to go somewhere.
 
14kcd91.jpg
 
AJ/FormS said:
If you find that you have a Trac-Loc, Check down in the holes where the axles go, and make sure the thrust-buttons are still in there;one on each side
Click to expand...

Unless the axle bearings were changed to the sealed "Green" bearings. They don't need the thrust buttons.
 
So the suregrip is out and now I understand how the cone type slipper works.

Only place I could find wear was where the cone meets the housing, and there are signs of the metal bar in the very middle has been quite hot, wearing on two edges more than others but there is no dip in the metal

726g6a.jpg


2e1d5w2.jpg
 
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I also put a little correction ink on the side, to see if the cone is 'bottoming out' on the housing, it is. Only just though...

20ptwzl.jpg


So there we have it. Thoughts? :)
 
did they use brass for any roller bearing cage? Are those heat cracks on the gear teeth face, ie run with no fluid or some big time heat? Just an observation. Dont you love that smell?
 
So have you located the source of all the metal? Did you inspect the carrier bearing? The races? If you haven't found out where the metal is coming from, your going to have to remove the pinion and check those bearings. Also can you down size the pictures you post? These are a little large and hard to get an over view.
 
Sorry yes I will resize, was trying to add detail by way of large images.

the bearings look okay not really looked at the pinion as of yet, do the surfaces on the truegrip look okay?
 
Well at the least you need to have .060 removed from the bottom of the two cones. You do not want them to bottom out in the case halves. If you can find.060 shims to add above the cones and in between the cone/ axle gear that would be a plus.
 
The area where the cones meet the housing is the only place I can see where metal has come away.

Is the unit destined for the bin or could it be re-used?
 
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