Long story. I swapped in some used 3.73's all was good and quiet, kept the 35,000 mile bearings, they looked good. Onlty thing is I noticed this high pitched whine while coasting. Also put on a AAM cover that directs oil off the ring gear through the cover and into the axle tubes for cooling. I got it for free thats basically the only reason for using it. I had to grind drain back slots for the oil to drain out of the axle tubes, the cover comes with templates.

25-40 miles later the front pinion bearing seized for a second, drove 1 mile max and got it towed home. The bearing was overheated and the cup had indentions from the rollers. The bearing still turned and everything was in place (it didn't fall apart).

But it galled up the pinion shaft so I got a new ring and pinion, new bearings, etc. Spent several hours after work getting the best pattern possible with the new gears. They are quiet now but that same whine is there mostly at 65 to 45 mph coast. I used a new crush sleeve every time and set pinion preload at 24 inch pounds.

I am using Mobil One 75w90 synthetic. Only thing different is I did not use any friction modifier.
Could that be the cause of the noise? Could the cover be pushing too much oil elsewhere?
The noise isn't that bad, can't hear it with the windows down but I think something is wrong.
What do you guys think?

 

Im not sure why you'd need oil in the tubes..Heck I had seals in my housing to keep oil from getting into the tubes...because if its in the tubes its not in the mesh where it needs to be... Also are you sure you werent supposed to increase oil level due to moving it into the tubes?I dont belive you'd even need to cool a diff on a street vehicle unless you were towing even then a good quality oil would be ok...sounds like a free part cost you alot in terms of money and headache..

 

I figured it couldn't hurt, it came off a '97 SS in a junkyard.
Heres some information about it.

 

TTT, I'm looking at the same cover for my Z because it's time to change my rear fluid and I figured why not get a new cover while I'm down there. I'd also like some more info about this cover. Hope everything works out for you.

 

I've been running that cover for some time on my 10 sec car with no problems!

 

Do you just run it or do you put any street time on it? I'm sure a 10 second car isn't quiet enough to hear a pinion bearing going.