So I took my beloved car into a shop to have the 2.73's chucked in favor of some 3.73's. Good idea, right?

After being jerked around for 4 weeks, I finally get the car back from these hacks after some heated debating. It sounded alright then, went on a test drive and all. But never going back to that shop again.

I've been doing a bit of light driving to aid in the recommended 500 mile break-in period, and I've noticed a whining noise getting louder and louder. I went through a ring and pinion before, i know the noise. So I stopped driving it.

Like I said, the car will not be going back to the same shop. They literally took a soldering iron to my A/C housing to get a bolt out.

Instead, I got adventurous and pulled the thing apart myself with some insight of a local rear axle builder (mostly 4x4 stuff), bought a dial indicator with a magnetic base, and some pinion paint. Backlash is a little tight, at .006", and the pattern seems to be ok. The drive side is slightly outboard, but the coast side is dead-middle. I put it all back together after inspecting the pinion gear (which looked good) and filled the diff with Valvoline LSD gear oil.

If these tolerances are within spec (which I think they are), what is causing the whining noise? Is this normal for new gears, do they have to 'wear-in'? I mostly only hear the noise while coasting at closed throttle.

Any ideas?

Nobody has any Idea?

Could it be that the pinion is tightened down too much and causing undue pressure on the pinion bearings?

Any advice will help. Thanks guys

Did you get a master rebuild kit or just threw in a new ring and pinion ? And what brand of ring and pinion is it ?

I bought the ring and pinion, its a Richmond Gear 3.73:1 from Summit. It came with pinion shims, no bearings or carrier shims.

I took the car to the shop, they replaced the carrier bearings, pinion bearings, pinion seal, and I would hope they replaced the crush sleeve but I can't be certain. I haven't pulled the pinion yet.

Did you break in the gears the right way or soon as you left the shop you beat the crap out of it ?

No, as stated in my original post I have been doing light driving to wear in the gears. It was recommended that I put 500 miles on the car before I did anything like that.

And, I also stated that I took the differential out and put it back together within spec. I'm no expert, but I didn't see any excessive wear or damage when I did this. No metal filings in the oil, no chips dings or wearing of teh ring and pinion themselves, and bearings looked good too.

I did notice that it was a little harder than expected to spin the axles to get the ring and pinion to mesh, even in neutral. Which is why I asked about the pinion crush sleeve being too tight.

Please don't think I'm ignorant enough to 'beat' on it after such work was done.

Well there are only really 2 things i can think of for gears to whine, 1 higher numerical performance gears are more prone to do it from certain manufactuers. 2 They ere not broken in properly ex. Richmond recommends that you drive 10 miles then park the car and let it sit till its completely cooled off, and you have to do this about 3 times i think. If the contacted pattern looked good like you said it did the the crush sleeve would be fine cause your pinion depth is set right and would show in your contact pattern.

Well, now that they are whining, how do I correct it? Do I keep driving as per Richmond's recommendations and hope it goes away?

Thanks for your input, I appreciate the help.

Well if there setup right and within spec and you already have done the break in with the heat cycles,then there's nothing you can do. You have some noisey gears. What gear oil are you useing ?

Used car lot trick of sawdust in the diff! J/K. FYI I have richmond 4.10's in my 94Z and they were set up by a GM master tech who does all the rear end work for our dealership and they were broke in just as Richmond recomended.....they whine like a fat kid banned from the candy store. They have been whiny since day one.

I'm using 80W-90 Valvoline Limited Slip Gear oil. Should I thicken it up a little bit? I wonder if Summit would accept them back....that whining will drive me nuts if it never goes away.

I have heard (no first hand accounts) that Richmonds are known for whining.

Depends on where you live and how cold it gets out. Try some 75-140 and it might quite it down some.

I live in Albuquerque, NM, so during the summer it doesn't get too cold here. I'll try swapping for thicker oil and see if it helps.

I'm also gonna call Summit and see if they'll accept the gears back on a "defective" cause.

The bearing preload might be off and the bearings could be causing the noise, not the gears. I would disassemble it and inspect the bearings, then go back and set the preload again.

So I pulled everything apart again, saw some little metal filings in the oil when I was doing it.

Checked the gears and carrier bearings, everything looked good. So I pulled the pinion...

Everything looked good there, except one major thing....no crush sleeve. I'm guessing this could be the root of my issues. Any ideas?

I bought a crush sleeve and a new pinion seal. Gonna put it back together soon, I'll let you guys know how it goes.