S6-37 6mt swap info (broken off from junk yard thread)

[D-O]

How big an improvement is the GS6-37? The standard E46 M3 gearbox is really the only thing I don't care for about the car.

[discoelk]

E46 M3 DS is what you use when putting an M3 subframe/diff in a 6 speed 330i so it should work fine in the M3 with the GS6-37.

[George Hill]

I thought the 330i driveshaft is the same as an E46 M3 driveshaft?

I think the rear length is the same, but I am not sure about the front.

I'll dig out some driveshafts later and take a pic comparing them.

[EthanolTurbo]

The transmission tunnel and transmission placement is exactly the same on all US RWD E46s.

Other than the driveshaft this will bolt in exactly like it would to its native engine.

IE to put the E46 GS6-37 trans in from a 330 you would use the 330 clutch, flywheel, TOB, Ford, shifter assembly and crossmember. I don't know how the driveshafts compare but I would imagine you would need either the 330/6MT driveshaft or a custom one. Hydraulics are all the same so you don't have to make any changes there.

I thought the 330i driveshaft is the same as an E46 M3 driveshaft?

[George Hill]

The transmission tunnel and transmission placement is exactly the same on all US RWD E46s.

Other than the driveshaft this will bolt in exactly like it would to its native engine.

IE to put the E46 GS6-37 trans in from a 330 you would use the 330 clutch, flywheel, TOB, Ford, shifter assembly and crossmember. I don't know how the driveshafts compare but I would imagine you would need either the 330/6MT driveshaft or a custom one. Hydraulics are all the same so you don't have to make any changes there.

[e46IX]

Did you ever make the tranny swap? Any reviews/insight you can provide would be appreciated. Thanks...

I'm probably still a month or two away before I bring the E46 M3 back home to finish the build. Just waiting on my engine builder to get the motor back together and I'll be sure to post updates here for everyone.

I have since acquired a few more transmissions. One of them is from a Z4M, one from an E60 530i, and the other 2 from E46 330's.

Apparently the Z4M input shaft is a bit longer than the 330 variant, I'll get em all side by side and carefully inspect the differences. From the outside they look identical, also the Z4M uses the same flywheel as the E46 M3, but has a unique clutch setup.

[BMWE46M3]

This just got shipped in, snuck this one from a wrecker who had it priced for cheap. Contacted Ronald to see if he can make an SSK for me hoping to get one from him by end of January.

Just so you guys know, the ZF 6-Speed in the E46 330i is also used in those early E60 525/30's with the M54 engine. I think it was 04-06 E60. I found mine like this priced under market value from car-part.

Did you ever make the tranny swap? Any reviews/insight you can provide would be appreciated. Thanks...

[BMWE46M3]

Just to confirm, are you planning on putting this transmission in an E46 M3? I’d love to hear your reviews if this is the case after you install it. If anything, there should be a great improvement just by installing the Autosolutions shifter.

[e46IX]

This just got shipped in, snuck this one from a wrecker who had it priced for cheap. Contacted Ronald to see if he can make an SSK for me hoping to get one from him by end of January.

Just so you guys know, the ZF 6-Speed in the E46 330i is also used in those early E60 525/30's with the M54 engine. I think it was 04-06 E60. I found mine like this priced under market value from car-part.

[bigjae46]

I think you're going to run into the same issue with used manual gearboxes...lack of maintenance and notchy shifting.

To me...the benefit of swapping in a ZF box is a BMW reman is a LOT less than a 420g reman the last time I checked.

pretty nice with the ASS kit, but it can groan into second if rushed

For some reason, I find this funny lol

[e46IX]

Every ZF 6 speed in BMW's is like that.

My E92 M3, my Supra, F87 M2's, etc.

You cannot rush the 1-2 shift in them.

I hate that.

There are a few folks that have done the swap, but it was more out of cost and availability rather than being an "upgrade".

I would recco, doing all your detents and swapping out to factory fluid and a good SSK like AS.

Not sure about that, I've owned maybe over 50 manual BMW's and haven't really experience that in other cars. I can do some WOT pulls slamming into 2nd in both my F80 and my E92 and no issues there. The F80 is a ZF unit for sure, I can't remember if the E9x uses a Getrag unit or ZF but the E92 has an Autosolutions SSK and that car shifts beautiful, the F80 will be getting one soon as well.

As for the MTF-LT3, it was all the dealer had in stock. I don't think they stock the LT2 anymore. Unless you guys are getting Pentosin or something.

[heinzboehmer]

The Supra is a GS6L50TZ but yaa it's smoother to engage than my E92 but you can't slam it into 2nd like I can with my 420s.

The smoothest 6 speed I ever had in a BMW was in my 2010 X3 but that was a 37 with low miles and an elderly original owner whom I bought the car from.

Never ripped on it because I used it to haul my dog around.

Funny enough I have a variant of that in my X5 and it's horrible.

Oh yeah you're right. Was thrown off by the S6-53 wikipedia entry. Hmm, sounds like I need to drive even more BMW ZFs. Doesn't help that there's a million different versions of the same transmission either...

[Sharocks]

Those are all S6-53s, so wouldn't generalize to "all BMW 6 speed ZFs" based on that experience alone.

I've been trying to drive as many BMW 6 speed ZFs as possible lately, to try and find the ideal one to swap in to my M3. Think my favorite one so far is the S6-45. Feels great and I don't recall there being any issue with 1-2 shifts. Drove it back to back with a GR supra and the difference was huge.

S6-45 is kinda hard to find and pretty fragile though. Friend that owns one had the reverse synchro go out and needed a new transmission. Seems to be a relatively common failure based on a quick internet search. Looks like all the BMW manuals have some sort of downside to them

The Supra is a GS6L50TZ but yaa it's smoother to engage than my E92 but you can't slam it into 2nd like I can with my 420s.

The smoothest 6 speed I ever had in a BMW was in my 2010 X3 but that was a 37 with low miles and an elderly original owner whom I bought the car from.

Never ripped on it because I used it to haul my dog around.

Funny enough I have a variant of that in my X5 and it's horrible.

[heinzboehmer]

My E92 M3, my Supra, F87 M2's, etc.

Those are all S6-53s, so wouldn't generalize to "all BMW 6 speed ZFs" based on that experience alone.

I've been trying to drive as many BMW 6 speed ZFs as possible lately, to try and find the ideal one to swap in to my M3. Think my favorite one so far is the S6-45. Feels great and I don't recall there being any issue with 1-2 shifts. Drove it back to back with a GR supra and the difference was huge.

S6-45 is kinda hard to find and pretty fragile though. Friend that owns one had the reverse synchro go out and needed a new transmission. Seems to be a relatively common failure based on a quick internet search. Looks like all the BMW manuals have some sort of downside to them

[Sharocks]

Alright making a return from my M3F hiatus to bump this thread. I've been in a Z4M coupe these last several years to get my S54 fix but I recently got another E46 M3 in my life that I'll be restoring.

So, I recently finished a SMG to Manual swap. Bought a used original manual 420G since I didn't want to mess around with machining work.

All new oem shifter bushings and fresh MTL-LT3 in there. Shifts like garbage.. sloppy, lots of play in gear, and takes quite a bit of persuasion to get it into gear when the trans is cold.

Now I'm no stranger to the 420G I know its always been a rough and noisy transmission, I feel like I got a high-mileage one with bad synchros or something since I just bought it used with no history on it. In retrospect I should have just paid a shop to convert my low-ish mileage SMG trans to manual but whatever that's already gone now.

I have the motor back out to refresh the whole thing on a stand, so now is a good time to consider swapping the trans. I can get a ZHP 6-speed easily through a buddy.

The Z4M 1-2 grind is a legit cause for concern, you can't go WOT and bang 1 to 2 in the Z4M. You have to baby that shift. The only good thing about the 420G is it takes a beating.

How many E46 M3's are out there running with the 330i/ZHP 6MT gearbox? Are the M3's with the ZHP trans also grinding that 1-2 shift? There's no solution in the Z4M world for this one, we just baby that shift.

I've had many ZHP's in the past, the ZF unit is nice in that car. It's smooth, quiet, and even when it's sloppy high mileage it still feels better than a sloppy 420G. The M3 driveshaft should bolt right up I don't think we even need to modify it.

Every ZF 6 speed in BMW's is like that.

My E92 M3, my Supra, F87 M2's, etc.

You cannot rush the 1-2 shift in them.

I hate that.

There are a few folks that have done the swap, but it was more out of cost and availability rather than being an "upgrade".

I would recco, doing all your detents and swapping out to factory fluid and a good SSK like AS.