i am assuming he means something like 75W-140 which IIRC ford trucks use. I don't think that is what GM specs call for.

Yep i had it backwards its 85w140, sorry fellas

Did they add posi additive Mike? Doesnt the Eatons take a Posi Additive? Did he take your car out for a test drive after the intall?

@Jeff yes, and yes. Its not a posi issue no friction modifier would cause clutch chatter not whine.
Could the back lash being alittle loose be causing this noise.

After a few heat cycles it isnt as loud, still loudest at 50mph, but havnt had it over that since the install.

I am in agreement with everyone else. The Rear should be quiet after its been rebuilt. After launching on it with a sticky tire then I can see it starting to get noisy but to be as noisy as it was before the rebuild then something is very wrong. Granted I had only 10 bolts but have had a 3.23, 3.42, 3,73, and 4.10 rears and they were all quiet. Some would start to howl @ 70 but only after a couple 1000 miles on them and some N20 runs @ the track. Still it was very tollorable and if I didnt point it out to someone you could not really hear it over the exhaust. What you have described Mike sounds like when my Axle bearing went out at the track and I had to drive the 80 miles back home to Va Beach. That was a very loud howling from 50mph on and would go away when I let off the gas.

My 4.10's were Richmond gears, and the 3.42's and 3.73's were Motive. My 3.73's made the most noise out of all, and the 4.10's were the quietest.

Does your 12 bolt have a T/A cover? If so could those bolts be pushing on the carrier caps to hard causing the whine?

My richmonds 3.73s only make noise on decel. I know when i set mine my backlash was alittle lose. Ive launched my 10 bolt countless times on slicks in the summer.
Its a hit or miss with gears some will be noisey other not. If you paid someone to install them have them redo it or take it to another shop.

Well?

Im pretty convinced its the gears. Talked to him, and took my dad for a ride in the car, he thinks its the gears as well.

So you got your rear end rebuilt because U needed a new posi, and it whined like a mofo and now after being rebuilt it still whines like a mofo? You and I were talking about this on facebook that you were saying the rear should not whine. You also told me that Motive used crappy Richmond gears and they dont properly set up the rears in the factory! Now you have used better gears and had a local shop set it up "properly" and it still whines just as loud. To me something is not adding up. It will be hard to sell a 12bolt that is not properly setup or that has a $hitty set of gears in it.

How about popping off the rear end cover and putting that while grease on the gear and turning your wheels? At least then you can see the gear wear pattern and that might help you in telling if they are setup correctly?

I purchased Motives because someone recommended them, they were made in the US but have switched production to china in the past few years and gone down hill. Its not nearly as loud after I put it thru a few heat cycles loudest at about 50 still tho.

Are you still trying to sell it or are you keeping it now?

Im keeping it for now

I bet the pinion depth is wrong. Pinion depth has more to do with gear wear pattern and noise. They probably just reused the old pinion shim and didn't bother to check pinion depth because its a PITA to press the pinion bearing on and off to get the right pinion shim. Do as Jeff said and check the wear pattern. BTW, my 4.11's in my 9 inch were noisey from day one, not ear piercing loud, just abit noisey.

it has a crush collar. If iirc they dont use both, correct?

You still need shims to set the pinion depth, crush collar or no.

Just checked my gear pattern, nice contact patch on the middle of the tooth drive and coast sides.

Take a picture of both sides of the ring gear teeth.

Well I brought it back to them to replace the pinion seal which was leaking already. I laid into it in gear to about half throttle a something let loose in the rear. Best way to describe it is it sounds like a turkey being put into a meat grinder alive on decel and metal on metal during cruise. Its now being lit on fire in the street infront of my house.

so... free for anyone to come get it?

So they did nothing else to address the existing noise?

Offer still stands at $500 for it.

I rolled te gear pattern and it looks fine..I never saw u made an offer.

Some admin deleted it

Raise hell. You got taken.

I told then the whole rear end of the car felt loose after I got it back from them I believe the axle bolts backed out because tge wheels ate wobbling