vanquish

+1 I was thinking the exact same thing. The preload has a very specific torque rating.

bigmackloud

I agree with the above. definitely sounds like your problem.

RP does make an 85w140. kinda rare but we stock it at the shop I work at.

99BlackPonyGT

but no 80w140, that ive seen atleast

98GTstang

thanks for the help guys, im going to back off the pinion nut and see if that helps at all.

stangalator

Haynes manual calls for "80w-90 GL-5 gear lubricant and adding 4 oz. of friction modifier when oil is changed"

vanquish

I think you need a new crush sleeve. Once you tighten it to set preload that crush sleeve is deformed according to the amount of torque placed on it. If you back the pinion nut off the crush sleeve is already crushed too far and may not fix your problem.

livefast1

DO NOT BACK OFF THE PINION NUT. like already said you've over crushed the crush sleeve and backin off the nut will cause major slop in the bearings and will almost definitly ruin your ring and pinion.

lenko

removed

08'MustangDude

I noticed I got a little bit of a whine when drained and filled my stock Diff...
Wasn't there before, but it is now, and I used the right synthetic gear oil.

It's an open diff, so I don't need the friction modifier.

WJL

Post is from 10 years ago just saying