I will soon have 4:10's put in my car. I figured I might as well get a new Eaton posi, just for peace of mind. I got the gears and gear installation kit already. I'm order the Eaton Posi tonight, do I need anything with it (installation kit, crush sleeve??) or is it just a bolt in part? Any other critical info is appreciated. Thanks.

P.S. We have 28 spline axles right??

 

ttt

 

I assume that since you have an M6 that you had a 3 series carrier (3.42 gears...) if you ordered the 4.10s did you do so for a 3 series carrier? If so then order a 3 series eaton posi. If you already ordered an installation kit you will have everything you need ..ie crush sleeve, carrier & pinion bearings, shims, ring gear bolts, pinion nut & seal...you may want to look at your axle bearings, too...These are bolt ins, but obviously only by someone who is experienced in setting up a rear...locally its about $200-350 in labor to do a carrier & gear swap...and yes if its a stock 10 bolt you have 28 spline axles...If you have any questions about anything call Randy's Ring and Pinion (check the back of most good car mags) they have been extremely helpful in the past...Hope this helps..
--Alan

P.S. The Eaton is a good choice