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

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G

GJUK

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Location
Nottingham, UK
350 miles since it was put together.
Suregrip - original, unknown condition but was working okay for ~500 miles prior to rebuilt
Brand new gears (CWP)
CWP fitting kit
Bearings not changed.

What do you guys think, ss it rubber ducked?

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That's pretty ugly. It needs to com completely apart and rebuilt. It will probably need all new bearings, seals and possibly a new ring and pinion.
 
That looks a bit extreme to me. Normal to find some amount of 'metallic' stuf as new stuff breaks in, but that don't look good.. you might have some rubber ducking going on. I'm sure someone more experienced than me can give you an idea exactly what is ducked..
 
I thought 8 .75 diffs were strong, why is mine made of glass?

I've driven it fairly steady :-/ Dropped the oil only to do the 'right thing' and... balls.

When out, is there any tell tail sign to see what is 'at fault' ?
How would you tell if the SG is 'rubber ducked' ?

Thanks,
 
Take it apart.
From rubber ducked I know nothing, But something inside there is fubar'ed.

Hey, I bet rubber ducked is a reference to one of those carnival/fair Kiosks where you test your ability to shoot ducks. When you hit it one,it is "shot".
Am I close?

FWIW;
Those bits do not look like SG parts, more like cast junk, like from the case or spider gears. Ima thinking it was peg-legged once too often.....take it apart.
 
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Tear it completely apart. Then post what you find. With that much metal it shouldn't be hard to find out what went south.
 
WTF does rubber ducked mean? Speak English. It doesn't look good. My money is on a bearing failure. Disassembly it to the bare housing, hose it out CLEAN and inspect everything.
 
post a pic of the pattern on the gears! it looks like maybe hard face ate ****. If that was a bearing I would think there would be bigger bits in there. Did you get a good pattern and correct back lash when you set them up? Did you have any noise, like whining gears or noisy bearing? Did they make noise on accel or decell?
 
Rubber ducked - London slang for ****ed yes.

The car is so loud you can not hear anything gear wise.

Here are some photos of it out though....

Out she comes...

To my untrained eye it looks okay, turns fairly free.

The halfshafts however, the bearings near the hub ends (carrier bearings?) are very stiff. lots of the metal bits appear brass/gold in colour.

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wiped towards the camera what was on the surface of the gear:

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All bearing I have encountered spin freely, the ones on the halfshafts turn but with quite a lot of force (covered in oil, though they may be; I can no spin them with all my force using one finger, I have to grasp them with my hand to turn them...)

Any thoughts please? :)

Thanks,
 
post a pic of the cross pin of the sure grip unit in the case ---spider gears may have welded to the cross pin ,, sheared the locating pin and wearing the sure grip case .
 
I put a super magnet on my drain plug, probably not the best place for it but it is better than nothing.
I notice there is one installed in my 833od seemed like a good idea.
 
do you have any set up compound? the pattern is tough to see with flash making everything shinny. Also, what was pinion pre load and back lash? If your side load was too much it will eat carrier bearings.
 
The gears look ok to me. I would tear it down and continue to inspect it closely. Could well be the cross shaft as already mentioned.
 
I'm still trying to figure out where that yellow stuff came from. I've never seen brass in an 8.75 diff that I did not put there. And the only place I ever put it, is in the cross-pin saddles. And it was a special hard rod that I had installed by a machine shop. And they promised me it would stay in there, to be harder than the surrounding metal. And they were right. So hurry up, get it apart.lol
You can leave the ring gear for now; I just want to see the saddles and the SG guts.
 
Take the 4 cap bolts out, and spill the case out onto the bench, ring-gear end closest to the table. See those small headed bolts sticking up? Take every second bolt out. Then back the rest of them out three turns each and move to the next one. They are under pressure from the springs inside. When they get close to coming out, put one hand on the case and press down to keep the upper half parallel to the lower half so you don't mess up the threads. If you see two cross pins, indicating a TracLoc, I suppose you could stamp the case-halves to make reassembly easy. But the cone type is obvious which way to align it on reassembly.
Once the hat is off just spill the guts on the table. On the 4spider type, I keep each spider on its pin to ensure long life at reassembly time, unless the pins are puked, then it don't matter.
 
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Am I going to lose any 'pre load' or previous settings and adjustment of the diff - as I've had it inspected this evening and everything 'gear mesh wise' is spot on...
 
But you still need to find out where that metal came from? Did you say the axle bearings were hard to spin?
 
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