slowbird6.0

okay guys need some help. I just change the fluid out of my 12 bolt Moser rear end as a auburn posi with 373 gears and 33 spline axles. I just put rial purple 75 90 gear lube. I still have a clunking no eyes only when I turn. Any suggestions if I should add friction modifier to it? Even tho royal purple has modifier in it already? Thanks guys.

thunderstruck507

iTrader: (18)

you will probably have to add some, the GM and Ford stuff being the best

Exeodus

iTrader: (1)

I would recommend it. Any dealer should have it.

Rob WS6

iTrader: (16)

Yup, youll need to add the posi additive. $13 at a gm dealer, just bought two bottles a couple weeks ago. One bottle should be fine for you.

joecar

Read your bottle of Royal Purple gear lube, it already contains friction modifier (it says "friction modifier" or "limited slip" or "LS").

cgormanZ28

Put some FM in it and do some very tight figure 8's at slow speed.

cgormanZ28

I have a Torsen and I'm running RP as well, I didn't have any abnormal
noises from mine. You have to be precise on the FM, don't add too much.

Chevyman1968

This is what I asked Bob with brute Speed and this was his answer below.


Originally Posted by Chevyman1968
I ordered the Moser 12 bolt yesterday from you and I have a few questions. For the u-joint. Do I use the factory u-joint if not what u-joint will I need and how many quarts does the 12 bolt need? I would like to have all this ready upon delivery.

Thanks in advance Ernest Bourgeois

Gear Oil - It takes 3 quarts

The limited slip differential design has been extensively tested with high quality NON-Synthetic 80W90 hypoid oils ( regular mineral based oil ) treated with GM or Ford friction additives ( 3 oz. of additive will treat 1 quart of oil ). To avoid differential clutch chatter ( noise ) and for optimum performance, use the oil and additive described above. Use of other additive and oil types may cause differential clutch chatter.

GM Friction Additive # 1052358

Bob

cgormanZ28

^ Perfect!

cgormanZ28

I have a question that I have not been able to get a clear answer on,
maybe you guys can help. Does Torsen AND Auburn require a source of
friction modifier??? If not, which one does and which one doesn't and
why? Thanks in advance. Sorry to ask within this post.

joecar

Friction modifier is for helping the friction components (clutches or cones) used in positraction style differentials to repeatedly grab/slip without shuddering.

Torsen has no clutch/cone friction components, and so does not require friction modifier.