6sphugger

hi, while putting in my ls7 clutch we realized that one of the pinion bearings in my stock rear is done. what i want to do, is replace the bearings and seals, and also put some 4.10's in. i realize everyone will say don't waste the money and put in a 9 inch or 12 bolt, but i just graduated from college and don't have the funds yet...i just want to run the 4.10's for probably a year until i can afford a 9 inch. my question is what usually causes the rears to go out?? is it hard launches on sticky tires, or will hard shifts in general break them too? I just want to make sure if i put these gears in that it doesn't break shortly after i put them in...i have an m6 and take my car to the track maybe once a month and run on street tires...also, im basically stock for right now(lid and cutout)

Thanks!

alamantia

iTrader: (10)

just curious, how did you discover a pinion bearing was bad while doing a clutch swap?

6sphugger

when going to put the driveshaft back in we realized there was a ton of play in the rear...my mechanic said it was most likely the bearing

corvet786c

iTrader: (6)

Before your discovery of this, was the rear making any kind of noise(whinning of loud clicking). If it was not just leave it alone. What year is your car? Do u have an auburn or torsen differential. My car is making a slight whining from 40mph to stop. But that is supposed to be normal my car has 66,000 miles Mods in sig.

6sphugger

well i don't think ive heard any kind of whining, but i do feel a sort of thud when getting on the gas hard and sometimes when shifting into second at low speeds...my car is 99, and i don't know if its auburn or torsen...how can i tell?

98_Formula

iTrader: (15)

i think the earlier cars had the torsen and later models had the auburn but don't quote me on that...

TheCarKid

My rear axle was ok with 4.10's for almost a year until I started building more power. It actually held up the the track once or twice a month, but that was on a street tire. The night I put some ET Streets on it, I snapped an axle. After fixing that, I tried it again and tore all the teeth clear off the pinion gear. And now I'm saving and getting a Dana S60.

The rear axles break because the stock 10 bolt housing is very weak compared to that of a 9" or Dana 60. 1.) A M6 car will put a lot more stress on a rear axle than a A4 car because the auto constantly has pressure on the gears, while in a manual, when the clutch is released hard, the gears slam and are more likely to fail 2.) The 10 bolt housing flexes causes the gears, bearing, etc.. to fail. You can try welding the case or "strengthening" the assembly but when it comes down to it, a 10 bolt isn't going to hold up to powerful launches, especially on sticky tires.

alamantia

iTrader: (10)

what do you measn by "play" the yoke was moving in and out of the housing?

6sphugger

by play i mean that you could move it back and forth like a quarter of an inch

alamantia

iTrader: (10)

Turning it clockwise and counterclockwise or pushing it in and out of the housing?

6sphugger

moving it side to side, not necessarily turning it....im not sure if you could push it in and out tho

6sphugger

so you think staying pretty much stock and running street tires the rear should hold up over the next year with maybe 10 or so track visits? also, is one brand better than the others in gear selection?

TheCarKid

Yea, I think staying pretty much stock and running street tires should save your rear axle. Keep in mind your 60' is prolly not gonna be where you want it cuz you'll spin off the line. As far as brand... everyone has their opinion and their own preference. I chose Motive at the time it was a lil bit cheaper than say Richmond. The reason I chose a 4.10 is cuz it compliments my cam well and it allows me to reach my power band quicker. I don't think you'll see any drop in E.T. in fact you may lose time cuz you'll spin a lot more.