will the Ring & Pinion Gear Set from a E46 M3 work on Z4M?

[AtoB]

i just spoke to the guys at Turner Motorsport.... they don't know....
does anyone definitively? i thought they were a direct swap.

[Starscream]

Part numbers are different,

But the pictures are the same on realoem,

Im sure it will "fit" if thats a pic of it but Im guessing the internal gear ratios would be different,

I know 100% the coupe and roadsters steering ratio is different,

M Roadster
http://www.realoem.com/bmw/showparts...69&hg=32&fg=10

M Coupe
http://www.realoem.com/bmw/showparts...69&hg=32&fg=10

E46 M3
http://www.realoem.com/bmw/showparts...69&hg=32&fg=10

[AtoB]

my goof.... i was asking about Ring & Pinion Gear Set... sorry

[Starscream]

Ahh

In that case yes
You can buy just the gears or the entire rear end unit from an M3

[AtoB]

Originally Posted by Starscream

Ahh

In that case yes
You can buy just the gears or the entire rear end unit from an M3

thank you!.... i'm still waiting to hear back from Turner Motorsport, at first they said no... but they would double check. seems they haven't had any experience with the Z4Ms.

[Z4Murder]

bumping an old thread. im looking to get just the 3.91 ring and pinion set, can anyone confirm that the e46 m3 3.91 gear set will fit in a z4m?!

[inTgr8r]

No personal experience, but I have seen it posted that the only difference in the rear diffs is the cover.
IIRC Diffsonline only lists parts as E46 M3, but many have bought parts there.

[Z4Murder]

Originally Posted by inTgr8r

No personal experience, but I have seen it posted that the only difference in the rear diffs is the cover.
IIRC Diffsonline only lists parts as E46 M3, but many have bought parts there.

thank you, yea im in the process of talking to diffsonline, but it seems like i can get the actual ring and pinion much cheaper through turner.

also, anyone else have any experience with a gear swap on here and know what other parts are needed?

thanks everyone

[inTgr8r]

Shims are required to set it up.
A good Indi tech should have all those things though. (or will get them)
JM2C, This is not really a DIY type of project.

[Starscream]

Yes M3 diff is the same as our diff bar the diff cover,
Same internals,

my 4.10's required no shims but shims and bearings are the same as any trans/diff shop would have,
nothing special in there that they haven't seen before

Make sure you use castrol SAF-XJ as the diff fluid,
I used the one with FM booster after some noise in the first 80 miles with the regular SAF-XJ and since I switched to SAF-XJ with FM booster the diff has been silent


Best mod Ive done this far

[Z4Murder]

Originally Posted by inTgr8r

Shims are required to set it up.
A good Indi tech should have all those things though. (or will get them)
JM2C, This is not really a DIY type of project.

cool thanks, yea i wasnt planning on doing this myself

Originally Posted by Starscream

Yes M3 diff is the same as our diff bar the diff cover,
Same internals,

my 4.10's required no shims but shims and bearings are the same as any trans/diff shop would have,
nothing special in there that they haven't seen before

Make sure you use castrol SAF-XJ as the diff fluid,
I used the one with FM booster after some noise in the first 80 miles with the regular SAF-XJ and since I switched to SAF-XJ with FM booster the diff has been silent


Best mod Ive done this far

thanks for the input! the local euro guy doesnt have the "proper tooling or gauges necessary to do a proper installation" WTF

looks like i will have to expand my search hmmm... anyone in western new york have an idea?!

[Starscream]

Its not an easy thing, and its not a DIY,
its not something you want to skimp on,

Ive done a handful of rear ends and tbh I hate doing them,

[nadaclue]

I wouldn't bother looking for a Euro shop to do it, it'll be harder to find someone who has the expertise. Look for a local transmission shop that works on race cars, particulary drag cars or road racing cars. Or even a shop that does work for off-roaders. These two places will have the most experience in rebuilding rear differentials, and they tend to understand how to get proper gear mesh better than most full service shops and that's by far the hardest part of the job. Just because it's a BMW rear differential doesn't make it special.

[Z4Murder]

Originally Posted by nadaclue

I wouldn't bother looking for a Euro shop to do it, it'll be harder to find someone who has the expertise. Look for a local transmission shop that works on race cars, particulary drag cars or road racing cars. Or even a shop that does work for off-roaders. These two places will have the most experience in rebuilding rear differentials, and they tend to understand how to get proper gear mesh better than most full service shops and that's by far the hardest part of the job. Just because it's a BMW rear differential doesn't make it special.

thanks for the input, my dad is a big hot rod guy and some of these cars are putting out serious power, all hand built. i'll have to go talk to some of the old timers, wasnt sure if the bmw rear end was anything special or not

[dekaliber]

Can anyone offer some perspective on how much labor+parts would cost if I supplied a stock LSD, had it rebuilt with 3.91 gears, and got it installed? Let's assume $100/hr for labor. Just looking for a general ballpark -- I'm guessing anything will be cheaper than the $2500+core Dinan option.