6 Speed Transmission Swap Options

**lbennyboobool** · 07-05-2018, 01:01 PM

I did a search that didn't really lead me to any useful information.

Can the e90 335 6 speed transmission be used with the s/m5x engines? Specifically to the e36. I know there would be custom parts involved like the trans mount, driveshaft, linkage, flywheel/clutch etc.

Has anyone done it and documented it? I feel like i've heard of it before, but i don't remember

**propcar** · 07-05-2018, 01:09 PM

I imagine it would be easier to source and swap either E46 M3 or 330i 6-speed, those have been documented/covered pretty well.

**lbennyboobool** · 07-05-2018, 01:20 PM

Originally Posted by propcar

I imagine it would be easier to source and swap either E46 M3 or 330i 6-speed, those have been documented/covered pretty well.

easier, probably so. just trying to gain knowledge, so not wanting the easy way out on this one

**propcar** · 07-05-2018, 01:31 PM

cool, I guess if you want a 6-speed transmission that works well you'd go for one of the proven examples.

But if you're willing to do custom driveshaft, linkages, flywheel and clutch your knowledge/ability on this is probably above average and to that I wish you good luck! As far as getting a response on this swap, I've never heard of it being done, there may be one or two out there, probably due to how impractical and non-advantageous it is. I'm sure it can be done though... enough, money, time, resources, and will power can get you places. But it sounds like you're going to start close to the ground floor on this one in terms of information.

It will likely cost more than doing the other swaps as well (which are costly as is). Even if you got the transmission for free... unless you've got all the labor, resources, machining, and fabrication covered.

**lbennyboobool** · 07-05-2018, 01:44 PM

The starting point would be if the transmission would bolt to the engine

just a side note: i find it funny that many people assume that someone asks something non traditional that they are wanting to do it and it will cost allot so more power to them. I'm merely trying to gain knowledge. There's allot of great minds in this forum and i'd like to learn. just because i asked a question doesn't mean i have the least bit of interest in doing. I want to spark a discussion. Learn, reason, and think through the process of something.

**pbonsalb** · 07-05-2018, 01:46 PM

No but Volosso in the FI Forum has some adapter plates made and a flywheel/clutch combo spec’d out. Not cheap. But better than a 420G.

A GS6-37 from an E46 330i will bolt up but torque rating is between stock 5 speed and 420G, much less than the 335i trans.

There is a diesel trans that bolts up, but it was never sold in the US. And the 1-2 ratios are for a low rpm diesel.

**lbennyboobool** · 07-05-2018, 02:02 PM

Originally Posted by pbonsalb

No but Volosso in the FI Forum has some adapter plates made and a flywheel/clutch combo spec’d out. Not cheap. But better than a 420G.

A GS6-37 from an E46 330i will bolt up but torque rating is between stock 5 speed and 420G, much less than the 335i trans.

There is a diesel trans that bolts up, but it was never sold in the US. And the 1-2 ratios are for a low rpm diesel.

are you saying the 335 trans can handle more torque than those 3?

**bigjae1976** · 07-05-2018, 03:07 PM

I’d look at realOEM and that should give you a good idea if the bolt holes will line up. I’d guess that you’d need to use the flywheel & clutch from the car the trans came from.

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**TH3 Shifty** · 07-05-2018, 04:16 PM

an easy way Benny, would be to take the thin metal shim/sheild thats between the trans and the block.. and take measurements or find a few trans you have access to and hold it up to them... thats your template right there.

**lbennyboobool** · 07-05-2018, 04:19 PM

Originally Posted by TH3 Shifty

an easy way Benny, would be to take the thin metal shim/sheild thats between the trans and the block.. and take measurements or find a few trans you have access to and hold it up to them... thats your template right there.

I never even thought about that! the shield would be an easy way to check and see.

i think it's not a direct fit the way phonsalb replied, but never hurts to mess around with stuff a little. I wouldn't think it would be off by too much

**pbonsalb** · 07-05-2018, 08:32 PM

ZF320 is 320NM, GS6-37 is 370NM, 420G is 420NM, GS6-53 is 530NM and underrated because BMW put it behind the twin turbo V8 in the F10 M5 that made 505 lbs torque — which is 684NM.

Some bolt holes line up on the GS6-53 and M/S5x but not enough for safe use. This has already been explored. If you are a good welder maybe you could cut the bell housing flange off and reweld it back on.

**jvit27** · 07-05-2018, 10:11 PM

Originally Posted by lbennyboobool

The starting point would be if the transmission would bolt to the engine

just a side note: i find it funny that many people assume that someone asks something non traditional that they are wanting to do it and it will cost allot so more power to them. I'm merely trying to gain knowledge. There's allot of great minds in this forum and i'd like to learn. just because i asked a question doesn't mean i have the least bit of interest in doing. I want to spark a discussion. Learn, reason, and think through the process of something.

That's fine to be curious, but this topic has been covered so many times that the answers you seek are all in the Search button. There's no new information or products..

There are only 3 options for a "bolt-in" 6 speed swap in E36. I have the ZF GS6-37BZ transmission in my Turbo E36. It is more difficult to retrofit but it holds the torque fine has a nicer feel.

Originally Posted by pbonsalb

There is a diesel trans that bolts up, but it was never sold in the US. And the 1-2 ratios are for a low rpm diesel.

The diesel transmission also clocks the engine differently as the the diesel engine mounts at a more vertical angle... So too many compromises to make it a viable option.

**lbennyboobool** · 07-05-2018, 10:16 PM

Originally Posted by jvit27

That's fine to be curious, but this topic has been covered so many times that the answers you seek are all in the Search button. There's no new information or products..

There are only 3 options for a "bolt-in" 6 speed swap in E36. I have the ZF GS6-37BZ transmission in my Turbo E36. It is more difficult to retrofit but it holds the torque fine has a nicer feel.

which one is the ZF GS6? I know the main three options are the Euro e36 m3 6 speed, e46 m3 6 speed, and the 330 zhp 6 speed. some people use the e39 v8 6 speed with an adapter or different bellhousing I think? I did think I heard talk of a couple people using the 335 6 speed transmission, but I could not locate any info on it using the search tool. thus I'm asking and learning.

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**jvit27** · 07-05-2018, 10:31 PM

Originally Posted by lbennyboobool

which one is the ZF GS6? I know the main three options are the Euro e36 m3 6 speed, e46 m3 6 speed, and the 330 zhp 6 speed. some people use the e39 v8 6 speed with an adapter or different bellhousing I think? I did think I heard talk of a couple people using the 335 6 speed transmission, but I could not locate any info on it using the search tool. thus I'm asking and learning.

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GS6-37BZ was what was used in the 330 ZHP, Z4M, and N52 powered cars. It requires a different flywheel/clutch/pp and modified linkage + crossmember.

The 420G from Euro E36 M3 bolts right up, and E46 M3 version uses a larger input shaft so you'll need the matching flywheel; everything else is Euro E36 fitment. E39 M5 also used 420G but its own bellhousing since the V8 was a different bolt pattern than I6.

The problem with the GS6-53BZ (335, 1M) is that the linkage will also need customization since it is a new generation transmission it has no lineage to E36. And there's really no point in reinventing the wheel when there are already three good options.

**pbonsalb** · 07-05-2018, 10:55 PM

The GS6-53 linkage issue is being addressed, as is the mounting. It’s stronger and cheaper used than the 420G. GS6-37 is for a moderate power car. Even the ZF320 5 speed will hold 500 lbs for a while if you don’t drag race. But for serious turbo torque driven hard, you need at least a 420G. And they are expensive. A GS6-53 with adapter and flywheel/clutch kit and linkage adapter makes sense if you are looking for a stronger trans. Still need a driveshaft if you make big power - you will twist an E36 shaft in two with decent turbo power. And then there is the diff — if you have decent power and can put it down, you will be snapping diff output stubs.

**lbennyboobool** · 07-06-2018, 09:13 AM

Originally Posted by jvit27

GS6-37BZ was what was used in the 330 ZHP, Z4M, and N52 powered cars. It requires a different flywheel/clutch/pp and modified linkage + crossmember.

The 420G from Euro E36 M3 bolts right up, and E46 M3 version uses a larger input shaft so you'll need the matching flywheel; everything else is Euro E36 fitment. E39 M5 also used 420G but its own bellhousing since the V8 was a different bolt pattern than I6.

The problem with the GS6-53BZ (335, 1M) is that the linkage will also need customization since it is a new generation transmission it has no lineage to E36. And there's really no point in reinventing the wheel when there are already three good options.

Does the Z4M with the s54 not have the same transmission as the e46 m3? The 420G?

Which n52 powered cars have the GS6-37BZ? Isn't that the motor the e90s have early on?

- - - Updated - - -

Originally Posted by pbonsalb

The GS6-53 linkage issue is being addressed, as is the mounting. It’s stronger and cheaper used than the 420G. GS6-37 is for a moderate power car. Even the ZF320 5 speed will hold 500 lbs for a while if you don’t drag race. But for serious turbo torque driven hard, you need at least a 420G. And they are expensive. A GS6-53 with adapter and flywheel/clutch kit and linkage adapter makes sense if you are looking for a stronger trans. Still need a driveshaft if you make big power - you will twist an E36 shaft in two with decent turbo power. And then there is the diff — if you have decent power and can put it down, you will be snapping diff output stubs.

Is Volloso (sp) the main one working on making this setup work?

**pbonsalb** · 07-06-2018, 10:50 AM

He is the only one selling a kit. There should be some up and running in the next few months. Wait and see if you don’t need to move now. If you don’t need as much strength, use the GS6-37 or 420G. I have broken diff output stubs, driveshafts, clutches and transmissions. I was going to try a 420G but if they break — and some develop shifting issues — they are expensive to buy used. I have a 420G and Euro support brace but it will be a while before I get around to selling it since I moved and my stuff is in storage until my garage is redone.

**NeilM** · 07-06-2018, 11:23 AM

http://www.zionsvilleautosport.com/s...onversion-kit/

Not cheap, but everything you need.

Neil

**lbennyboobool** · 07-06-2018, 12:07 PM

Don't the 420G transmission have brass syncros? I think i heard that they can get roughed up pretty easily and make shifting less than ideal, but i could always be wrong. I'm guessing the GS6-37 doesn't?

**RRSperry** · 07-13-2018, 06:45 AM

It depends on what you are going to use the car for. When I put the 420G in my car, I had no idea just how loud and clunky that transmission was. Since my car only makes 320 rwhp, I'd probably have been happier with the GS6. It's smoother and quieter than the 420G.

Anyway, all in, I think it was about $4K. (used 420G, drive shaft. new everything else. UUC flywheel clutch (e46 M3) 325 slave, cross member, new CSB, new Rogue SSK, guibo, shift knob...)

If i were to do it again, I probably wouldn't...

**lbennyboobool** · 07-13-2018, 12:30 PM

Originally Posted by RRSperry

It depends on what you are going to use the car for. When I put the 420G in my car, I had no idea just how loud and clunky that transmission was. Since my car only makes 320 rwhp, I'd probably have been happier with the GS6. It's smoother and quieter than the 420G.

Anyway, all in, I think it was about $4K. (used 420G, drive shaft. new everything else. UUC flywheel clutch (e46 M3) 325 slave, cross member, new CSB, new Rogue SSK, guibo, shift knob...)

If i were to do it again, I probably wouldn't...

Is the GS6 quieter? I don't think i've driven a car with one. I've driven an e46 m3 a bit and didn't mind it.

How often do you actually use 6th? Since 1-5 are the same as the ZF i'm curious as to how much you actually put it in 6th

**MauiM3Mania** · 07-13-2018, 12:55 PM

6th is nice if you have a steeper diff ratio. My E36 has a 3.91 final drive and in sixth, the engine is turning about the same as a 3.23 in fifth.

Even though I don't have an interstate highway, sixth is nice to keep the revs reasonable.

**pbonsalb** · 07-13-2018, 09:48 PM

Originally Posted by lbennyboobool

Is the GS6 quieter? I don't think i've driven a car with one. I've driven an e46 m3 a bit and didn't mind it.

How often do you actually use 6th? Since 1-5 are the same as the ZF i'm curious as to how much you actually put it in 6th

Depends on how much highway driving you do and how fast you drive when on the highway. If you stick to 65-70, the 5 speed is fine with a stock diff or even with a 3.38 or 3.46. Go to 3.64 or shorter and you want a 6th.

I want the 6 speed for durability. Have broken 2 five speeds and need a stronger trans to handle 600lbs rwtq from the turbo S52.

On my 08M3, I have the GS6-53 and 3.85 diff from the factory. I could almost use a 7th gear since I am turning close to 4000 at 90 mph. Or a longer OD gear — the reduction is only to 0.87.

**lbennyboobool** · 07-14-2018, 02:05 PM

I rarely go on the highway and if I do I only go around 80. I think I'm wanting a 3.64 or 3.73 diff but haven't completely decided. I like how the 3.46 feels now. just weighing options at the moment. I like the thought of a 6 speed but I don't know if I would use it very often

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**pbonsalb** · 07-14-2018, 11:37 PM

I would try the shorter ratio and go from there. I ran a 3.64 for a year while supercharged and it was my favorite diff out of 3.23, 3.38 and 3.64 that I ran while supercharged. The only thing was that 80mph on the highway got old fast at 4000 rpm with a moderately loud exhaust and left me thinking about a 6 speed conversion. If you don't drive much on the highway, this won't be as much of an issue. I put the 6 speed money towards a turbo conversion. The turbo made so much torque, I changed to a 3.15.