txh0tb0i972

iTrader: (63)

ok i just got a brand new set of 3.73 and im ready to install them but what kind of gear oil do you say i use and what do you think is the best.... please give me your opinion thx...

if it makes any difference my car has 90k miles on it

dailydriver

It all depends on which differential you have. DO NOT use synthetic gear oil IF you have an Eaton or Auburn. Synth is OK (even recommended?) for Torsens or other worm gear type diffs (Eaton/Detroit Truetrac).

BlackScreaminMachine

iTrader: (17)

I forget the grade, ill look tonight, mine was GM/Moser recommended dino oil. No additive in mine since its a tru trac. But for you, do get the GM LSD additive.

NJSPDER

iTrader: (2)

i use sythetic in everything, never had any problems related to oiling. a few failures related to extended periods of abuse, but that is what the car is for

WJ SOM SS

iTrader: (11)

synthetic or regular gear oil will work. what's most important is to run your new gears thru at least 3-4 heat cycles before pounding the snot out of them. if they're set up properly, and heat cycled properly, they won't howl like a banshee. WJ

02SOMWS6

iTrader: (6)

If you want it to last. Do not put synthetic oil in your rear

ULTIMATEORANGESS

iTrader: (4)

just use some regular oil for break in. after 500 miles put some lucas with GM additive. worked for me.

txh0tb0i972

iTrader: (63)

what do you consider the perfect heat cycle.... miles.... mph.... and how long do i wait to start the 2nd cycle

WJ SOM SS

iTrader: (11)

I was told: right after install, a 10-15 mile MODERATE drive--no highway speeds. Bring the car back and park it---let it cool down COMPLETELY. 2-3 cycles of this with NO hard pulling on the gearset (such as winding it up thru the gears). Dump the oil, throw in new oil and additive (if needed). If the rear stayed quiet during the heat-cycling time--it was set up correctly. If not---something's wrong w/install....Maybe someone can add something constructive to this.... WJ

chae

iTrader: (8)

Good to know.

To the original poster do you have an M6 with 3.73's. If so what can of improvements did you see as far as track times/street manners? Thanks.

WJ SOM SS

iTrader: (11)

BTW, this is for street/occasional race gears, not race-only gears. Solid crush collars and correct setup make the difference in race-only gears.....and they usually always are a little noisy. WJ

txh0tb0i972

iTrader: (63)

its a m6 for street.... and ok ill do what i have been told .... do i buy 75-90 or what wght. is better?