RB Racing

iTrader: (1)

I bought my 02 WS6 just in fall and I'm looking at a couple of mods particularily a gear swap from the stock 3.42's.
My car is an M6 car with 425rwhp and it will be a street car only mostly city with the odd highway run. Stock tire height.

My buddy said to get the Motive's that have the longer part # as they are lapped in from the factory and the better ones to get. Anyone know if there is different part #'s in the Motive line?

Are the stock diff's made by Borg Warner?

Still on the fence on a ratio choice looking at either 3.73's or 3.90's I just find first gear really tall and with sixth being so over driven a gear swap would make it nicer to drive in the city.

Also where is a good place to purchase Motive's for a good deal.Thanks.

lt1cam/z

advance carries the motive brand ata decent price but the 390s are discontinued through them but summit still has them for $200. 373s at advance were about $180 for ring and pinion. the gm rebuild kit was $70(bearings,shims etc) motive part numbers were gm7.5373or gm7.5390 (the7.5being the rear end depending)

SMOKNSS

iTrader: (3)

I have always ran Motive or Richmond gears and never had any problems out of either.

RB Racing

iTrader: (1)

My car only has 30k with Royal Purple so the bearings should be fine.

Anybody use Drivetrain America?

01ssreda4

iTrader: (96)

Motive part numbers: GMxxxxx = stock like quiet
.................................G8xxxxx = noisy and less forgiving about how they are setup.

My experience. And all gear sets are lapped in after they are made so you're friend is

RB Racing

iTrader: (1)

O.K. so GM7.5-373 or GM7.5-390 are the quite ones.
Motive doesn't list the 3.90 part # but a search shows they are available.

redbird555

iTrader: (14)

01ss is right. The motive are all lapped at the factory and they don't make 3.90s in the normal street headset you will have to get the orange box gears which as said do tend to be a little noisy.

Mine have a touch of whine on decel but you have to really listen for it, on top of that they are a little stronger alloy which Is why they tend to make a little noise. In happy with mine I feel it's a great ratio for the m6

farmington

iTrader: (14)

i was told that the gears made by American Axle were quieter than aftermarket gears, but the aftermarket ones were a little bit stronger.

gm_jim

My Superior's (made by American Axle) have been quiet as a mouse for over 10 years. It's all in the setup.

RB Racing

iTrader: (1)

My car isn't super quite anyway so I'm not sure a minimal amount of gear noise will be that big of a deal.

01ssreda4

iTrader: (96)

Yep 3.90 is the G8 part number only.

RB Racing

iTrader: (1)

Looks like the GM7.5-390 is discontinued so G875390 may be my only option.