speed2b

I finally did the swap to 4:10s in my 95 Z28 a4 with a built trans.I did A complet rearend rebuild and it made a big diffrence.The lanch is very strong and my shift kit really came alive.There is a wining noise in the rear just wanted to know will it go away or stay the same. Sorry about spelling and stuff i have parkinson hard enough just to type.

ZFreie

Stock 10 bolt?

From what I have read on here is they whine if not shimmed properly. Did you see what the sweep was on the gears when you put them in?

Dave357LT1

If you just rebuilt the rear and didn't break it in right it will make noise. My motive 3.90's had a hum on decel

trilkb

iTrader: (4)

Ive never experienced it, but I would suspect a rear end that whines always will. When one doesnt whine, thats when you know it was set up very very good. But even if it does whine, its not a sign that its about to blow up and needs to be fixed ASAP, some gears just do that.

Thats atleast what ive read, if im full of **** someone can correct me.

speed2b

yes stock 10 bolt

speed2b

it just does it on decell

ZFreie

Well seems like it might not be a big deal, I was assuming it was all the time lol

What brand gears did you put in?

speed2b

summit 6 cut.how do you break them in

96lt1m6

iTrader: (31)

A couple of heat cycles generally do the trick....... Be easy on them for a while (200-300) miles

speed2b

Thanks for your help. I will break it in today

bowtienut

iTrader: (1)

Without going back in to re-set them up, if they're whining now, they will always whine. And.......re-doing them is no guarantee that it will stop.
Out of all the GM, Motive, and Richmond gears I've used that were set up by a guy who knows it well (I'm excluding the one set I did myself!), I've had only one set (a Richmond 5.57 set for a GM 8.5" 10-bolt) that made any noise at all.
From what you describe, the whine you hear will never hurt a thing. It has nothing to do with how you break them in.

Good move on going to the 4.10's .......miles of smiles

RamAir95TA

iTrader: (2)

The gear setup is EVERYTHING. Being meticulous ensures a quiet rear. Meticulous means setting the pinion depth and backlash within .002" of spec. Meticulousness is EVERYTHING.

Breaking them in is more about heat cycles than actual mileage. Don't expect to just go drive for an hour and expect them to be broken in. I would drive for 10-15 minutes, allow the rear to cool COMPLETELY, then repeat 2 or 3 more times after that. After 4 or 5 heat cycles AND a few hundred miles you should be good to go.

For what it's worth though on a 12-bolt or 9" once you put a few heat cycles on them it's safe to go tear ***. No need for a mileage-specific break-in on those bad boys.

speed2b

the guys i had install them said it to .005 i don't know about how all that works but he said the pinion was set at 37. they had to reset it after the pinion bearing failed after a short drive. thanks for the break in advise been doing that all day. with my shift kit it spins going into second just normal driving. thats not going to effect the break in is it.