Alfa Romeo Bulletin Board & Forums - View Single Post - Differential noise - 74 Spider; 40k miles
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post #8 of (permalink) Old 10-06-2017, 09:41 AM
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Join Date: Jul 2006
Location: san diego CA
Posts: 5,090
Lots of misinformation out there.

a. Pinion preload is not set by nut torque to an appreciable degree. It is set by the collar and shims on the pinion shaft behind the rear pinion bearing.
b. Pinion position is set by shims behind the bearing shells.
c. Putting gaskets on the axle tubes has no effect on crown preload or pinion alignment at all. It only effects the depth of penetration of the axle splines into the spider (EDIT -- only the "small diameter" axle tube, NOT the diff side case axle tube)
d. I agree 100% that if the seal is replaced, it is best to return the nut to the previous position.
e. You might try redline 90-140 NS gear oil to see if that helps. it might (edit -- its probably 75-140NS!!)
f. Don't rebuild a diff unless you have the right tools, and a lot or patience. (Edit -- read item f twice then once again if you have a doubt)
g. Lash is a factor in diff noise as well as pinion position relative to crown gear.

74 GTV with 10548's and Ingram pump
71 Spider 1750 BOMBER ; 1995 LS 78K tight fast car

Last edited by goats; 10-06-2017 at 01:03 PM.
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