mvvette97

iTrader: (18)

I have been fighting gear whine with several sets of 4.10s. I hear alot of time the stock pinion shim works the best to start out with. my problem is that i sold my stock gears with the bearing and shim so I have no idea what shim I had originally. I wanna try a stock shim for starters so what have most of your stock rears had for the shim size? We have a .035 in it right now but I think it's a little deep. Is the stock size like a 25 or 30?

toadzq8

iTrader: (43)

The factory shim should allways stay with the rear end (I know it don't help you much now) but that only gets you ball park on correct pinon depth. wipe pattern, back lash, diff shims etc etc are factors controling pinon shim size. So the factory shim don't allways work out when you change gears. Some mfg's gears naturaly whine more than factory gears, so first question would be what mfg gears you been using.

mvvette97

iTrader: (18)

I have the AAM 4.10s. I had the mechanic do the install for me but to me he just hurried through it. I don't feel he done a good job since it makes alot of noise. I know he knows what to do because he has set up rears for years at the shop he works at and never had one make noise yet. I think he just didn't want to pull the pinion again to change the shim. I looked at the pattern and I thought it looked too deep.

Scott@DrivelineSolutions

iTrader: (22)

Start out with .034 pinion shim and check the pattern. I've had shims range from .032 to .036 on average.

wrd1972

iTrader: (12)

I remember mine having a .020". I think.

TransAmdriv3r

iTrader: (10)

yeah, same here mine was a .026

mvvette97

iTrader: (18)

Well i pulled the cover and checked the pattern. The drive side pattern is from the center clear out to the outside edge of the tooth. In my opinion that doesn't look right at all. I'll get a picture of it and post it

mvvette97

iTrader: (18)

Here is the pattern I have that the mechanic set op. I don't think it's right because it is loud on the drive side.

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wrd1972

iTrader: (12)

Coast aint real bad but but is a touch toe heavy, drive is a mile off toward the heel. Changing the backlash will move that pattern either better or worse. Pinion depth looks pretty close. Dont run them with this setup.

Randy WS6

iTrader: (69)

mine was .031"

mvvette97

iTrader: (18)

well I just went out and checked the backlash and to my surprise it's 14 thousands. I know AAM say about 4 to 6. Could the backlash cause this terrible whine on the drive side? It's pretty quiet on the coast

mvvette97

iTrader: (18)

It also has a .035 pinion shim in it. I'm thinking of trying a 30

JimsWS6

iTrader: (1)

every 8.5 truck and 7.5 I've worked on came with .35. The only time I wasn't able to use the stock shim was when i went from 3.73 in my ZR2's 8.5 to 4.56 gears. Had to increase the pinion shim to .42.

Looks like you need to change your shim. And if your backlash is 14 you need to increase the drivers side shim pack, and take away from pass.

mvvette97

iTrader: (18)

I just pulled the pinion bearing off and the shim is a .034 Should I try a 28 or 30 and then st the backlash to like .006?

SS SLP2

iTrader: (8)

I am with WRD 1972, I would try with your peion shim to start with, I would work on backlash, 4-6 should be good with the AAM, but the AAM 2 cut gear set up with a differant pattern than the 5 cut gears, I can not find the link rite now do a search for AAM setup
my .02' Johnny

mvvette97

iTrader: (18)

Should I go thinner on the pinion? Since I have a .034 now shoud I try a .029 or 30? Oh I found the link to the pattern for the two cut gears