Help me please someone, GMC AWD Noise

Hello to all,
I have a 96 GMC safari V6, AT, AWD.
The front differential drive shaft (from transfer case) was removed a few months ago because it was bad,(vibrating at high speeds) and consequently,
it drove fine in 2wd at the time. Now, above 35 MPH it starts a steady hum in the front end. The pitch increases with speed and it seems to level out at cruising speed on the highway.
I have pulled the front diff in an effort to find the problem. Luckily, I must say that the diff it was real easy to pull. It seemed that the backlash on one side was a bit excessive -( I don't know the Specs) and it seems on one side the gears may be rough like they are catching a bit on the edge of teeth. Will this be hard to rebuild? I have never rebuilt a diff or AT before; gearboxes/engines/diesels yes. Based on description would diff be at fault?? CV's and bearings seem okay, no play at all. So now I need info and advice, I can't ID the differential, no tag and the stamped numbers don't match anything. Any help appreciated. Thanks, tink
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"Tink" wrote

know
That's impossible to tell. I wouldn't be pulling a front diff out at work without putting it up on a hoist and running the vehicle while listening to the front diff. Oh right...you don't have the front driveshaft installed.
If you are lucky enough to actually find the problem you are looking for in that front diff...I'd be concentrating on the side bearings and pinion bearings. Never mind about marks that you might see on the crown and pinion....most of them have all sorts of marks on them that scare the living daylights out of the novice, but are perfectly normal.
If you want to check backlash properly...you need to measure it at the pinion yoke and divide by two. In other words, if you measured .020" at the yoke....you actually have .010" of backlash between the crown and pinion. Do you have a dial gauge?
Hopefully, some of this will help.
Ian
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Front Stub axel bearings? How many miles/kilometres? Respectfully Rolf
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