I thought it would be a good idea to post this question here. So here it is.

I have a 318 diff, 3.46lsd. I always broke either the spider gear, or stripped the axle spline on this diff.

After mutilating 3 3.46lsd diffs, it was obvious it would not hold up to any type of abuse.

I bought a 3.91lsd. Its great for autoX, but my car is a dual purpose car, and I am tired of being at 4000rpm @ 75 all the time.

Heres the plan:
Swap the 3.46 ring and pinion from the 318 into the larger 3.91lsd housing, using the limited slip unit from the big diff. I know these diffs have a different length, but will I be able to rebuild the big diff with a 3.46 ring and pinion from a small one? Thanks for your help.

why dont you try and get a 3.46 that came from a 6 cyl and uses the 188mm gears?

they sell for like 150 on ebay

The smaller gears won't work in the larger housing. Even if they did, you'd still be breaking them.

As skratch posted, find a 3.45 from an E34 and swap the gears in to a E36 housing.

who built your diffs,If there not built right they wont last.I have blown 2 sets of 188mm gears also so maybe you should go with some 210s

but gears from a 318 wont last long even if zues himself builds them lol

these should be 188mm gears and fit your housing

http://cgi.ebay.com/ebaymotors/BMW-DIFFERENTIAL-DIFF-3-46-E28-528-533-535-325-E30_W0QQcmdZViewItemQQcategoryZ33731QQihZ005QQitem Z150045172149QQrdZ1QQsspagenameZWD1V

who built your diffs,If there not built right they wont last.I have blown 2 sets of 188mm gears also so maybe you should go with some 210s

but gears from a 318 wont last long even if zues himself builds them lol

No one built my diffs, they were just used diffs I purchased. I work in a shop where we specialize in porsche, mercedes and bmw, so I can rebuild a bmw diff. I just wanted to know what fits.

I didnt break the R and P on the diffs, I destroyed the limited slip part

Thanks for the link. But does that mean that an E30 diff can be gutted out and installed in a e36 diff?

No one built my diffs, they were just used diffs I purchased. I work in a shop where we specialize in porsche, mercedes and bmw, so I can rebuild a bmw diff. I just wanted to know what fits.

I didnt break the R and P on the diffs, I destroyed the limited slip part

Thanks for the link. But does that mean that an E30 diff can be gutted out and installed in a e36 diff?

bmw uses 3 sets of gears in there cars

Bmw uses 3 sizes of differentials. The 3 sizes are a referance to the diameter of the ring gear.

First the small 168mm differential, which is comonly found in the 4cyl chassies like E30 and E36 318, 2002, and E21 320 and 323.

The second or medium 188mm size is found in most 6cyl chassis. Such as E30 325, e36 325 328 323 m3, E36/7 318ti, also Z3 coupes, and roadsters,E46 325 323 328 also E30 M3, and E24 6 series.

Finaly the large Differential 210mm. This unit is found in all 8cyl, and 12cyl chassis. Like E32 740 and 750, E31 840 and 850, also E34 M5,E24 M6, and E46 M3.

All BMW differentials weather LSD or open use one of theese 3 sizes. The easiest way to tell what you have in your car is to count the bolts on the output Bearing race/ oil seal mount behind the output flange. This flange will have 4 bolts for a 168mm, 6 bolts for a 188mm, and 8 if it is a 210mm.

pm me if you want and I can give you a shop that has 3.46 lsd with 40% lock up and 3 clutchs for under 700 and completely rebiult

pm me if you want and I can give you a shop that has 3.46 lsd with 40% lock up and 3 clutchs for under 700 and completely rebiult

metrix mechanics?

metrix mechanics?

metrix motorsports

metrix motorsports

Anyone bought a diff from these guys..

Anyone bought a diff from these guys..

I saw someone selling one of their rebuilt diffs on ebay a week ago or so and was wondering the same thing.