2000 750il M73 Manual Transmission Swap

**masu3701** · 01-22-2019, 12:47 PM

Hello all,

I have a 2000 750il and would like to know what it takes to swap to manual transmission. I see people doing it on 740s using a 6 speeds trans from a 540i, but
haven't seen anyone done it on a 750. Is this doable ?

Anybody done it? Please shine some light.

thanks

**tjpike** · 01-22-2019, 04:52 PM

Originally Posted by masu3701

Hello all,

I have a 2000 750il and would like to know what it takes to swap to manual transmission. I see people doing it on 740s using a 6 speeds trans from a 540i, but
haven't seen anyone done it on a 750. Is this doable ?

Anybody done it? Please shine some light.

thanks

It is doable, but it would require a 6 speed from an 850i or 850csi. Which are not available new, and are rarely if ever available used.

Even if you are able to find the transmission, you might have to make some modifications to the bell housing to adapt it to fit the m73 bell housing. Along with a custom driveshaft.

Not to mention the coding cause there was never a manual v12 offered, so it's not as simple as just loading a tune.

It's a lot of work, but is doable if you want to spend $$

**Narlift** · 01-22-2019, 05:19 PM

You'll never get it done dude, sorry but just forget the thought.

**masu3701** · 01-22-2019, 05:20 PM

Originally Posted by tjpike

It is doable, but it would require a 6 speed from an 850i or 850csi. Which are not available new, and are rarely if ever available used.

Even if you are able to find the transmission, you might have to make some modifications to the bell housing to adapt it to fit the m73 bell housing. Along with a custom driveshaft.

Not to mention the coding cause there was never a manual v12 offered, so it's not as simple as just loading a tune.

It's a lot of work, but is doable if you want to spend $$

Thanks. It sounds like its not worth the trouble and cash.. my 750 is in excellant shape, so wll just leave it as it is.

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**Narlift** · 01-22-2019, 05:49 PM

Goooooood luck big guy. it wouldve been done already.

**CPHES** · 01-22-2019, 07:17 PM

The owner of UUC did it. Cool, but expensive - old Bimmer magazine issue #35? Documents it. Yes, your need an 850 manual, as the 420g can’t handle the v12 load.

**masu3701** · 01-22-2019, 07:22 PM

Originally Posted by CPHES

The owner of UUC did it. Cool, but expensive - old Bimmer magazine issue #35? Documents it. Yes, your need an 850 manual, as the 420g can’t handle the v12 load.

Yes..those are hard to come by. I will leave it alone. May get a 740 to play with and leave my 750 as is in excellent condition

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**CPHES** · 01-22-2019, 08:25 PM

Board57796 / Buck Clifford has an 01 750iL - look at his mods. I’m part of the way there / lots of the parts in my garage - now I need time. Yes, if you want a manual e38, 740 is the platform. Trying to scratch my manual itch by converting the 540iT.

**gusdog** · 01-22-2019, 10:20 PM

Just a thought experiment here, but could you take the entire engine / tranny / modules (maybe even the diff) from a wrecked 850 and make it work? Sure, you'd need a custom drive shaft, but that's doable.

I can't picture the instrument cluster on an 850, but I guess you'd run into some issues there. Any other sensors that wouldn't be swappable?

**tjpike** · 01-22-2019, 11:19 PM

Originally Posted by Narlift

Goooooood luck big guy. it wouldve been done already.

It's been done

- - - Updated - - -

Originally Posted by gusdog

Just a thought experiment here, but could you take the entire engine / tranny / modules (maybe even the diff) from a wrecked 850 and make it work? Sure, you'd need a custom drive shaft, but that's doable.

I can't picture the instrument cluster on an 850, but I guess you'd run into some issues there. Any other sensors that wouldn't be swappable?

This is doable, except, finding an 850 will probably be very hard as they're very rare and buying one may exceed the purchase price of the E38.

**masu3701** · 01-23-2019, 01:23 PM

Originally Posted by tjpike

It's been done

- - - Updated - - -

This is doable, except, finding an 850 will probably be very hard as they're very rare and buying one may exceed the purchase price of the E38.

Yes finding a 850 engine is difficult. I will leave it as is and mind other mods i can do

**Narlift** · 01-23-2019, 08:18 PM

I'll paypal you $1000 if you get this completed. That's how confident I am it won't happen. You'd be like..the first one for one thing.

**KSEADUB** · 01-23-2019, 11:02 PM

^—

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**masu3701** · 01-24-2019, 05:44 AM

Originally Posted by Narlift

I'll paypal you $1000 if you get this completed. That's how confident I am it won't happen. You'd be like..the first one for one thing.

Dude whats up with you? We all agreed that it is duable but sourcing a 850 donor is difficult.
I also mentioned that i will be leaving it alone as it is. So we all agreed that its not happening.

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**007008** · 01-24-2019, 10:32 AM

The expensive bit is finding the gearbox. The other problem with the facelift cars is there was never manual software written for the v12, so you would have to live with the SES light. I'm not sure what UUC Rob did.
It is possible and has been done before to cut the bell housing off the transmission and weld the v12 flange on a v8 trans.

**Richard454** · 01-24-2019, 03:47 PM

Here's a cheaper way than getting a hold of a 420G and a E31 flywheel / clutch/ throw-out...

Trans adapter for the M70/73 block

BMW manual gearboxes list:

BMW M20
BMW M50, S50 S5D-250 / ZF-310 S5D-310
BMW M52, S52 E36 M3 5-speed ZF-320 S5D-320
BMW M54, S54 E46 M3 6-speed Getrag 420 226.0.0440.97 / E36 M3 Getrag 420 226.0.0161.91
BMW M57 Diesel (5 speed) GS5-39DZ e39 530D 525D, e46 330D 1434256 ZF 1065401011

http://www.pmcmotorsport.com/44,adap...w-m70-m73.html

This is how I put a 6 speed behind a V12-no adapters were around at the time I did it.

Here's a couple of pics of my BMW auto bellhousing milled down and a plate of 1/2 aluminum drilled to fit the standard GM/Muncie bolt pattern. HOWEVER the T56 uses an integrated bellhousing and this approach won't work w/ it.

Flywheel and clutch-

It's not that tough- just a little tedious to make sure its balanced/centered.

There are several companies selling clutches- most have the bolt dimensions for their clutch on their website- not tough to find. I went w/ a RAM Powergrip 10.5"- the 11" clutch is TOO big for the 13" E31 Flywheel. FWIW- this set up was LESS than $300-pressureplate/disc/TO bearing....or about the same price as JUST a BMW T/O Bearing....

We pulled the dowel pins then surfaced the used BMW flywheel.

Set it up in a rotary mill and proceeded to drill and tap for the pressure plate bolts- six of them.

We then bolted the pressureplate down-and using a small dial indicator( to fit inside the clutch fingers) measured the run out on the machined disc surface. After we got it down to less then a thousandths -we clamped it down.

Then drilled new dowel pins- through the pressure plate. The stock Chevy doesn't use dowel pins- but I didn't fell good about just bolting it down and hoping it was close enough...

After the dowel pins were placed- we marked the pressureplate to assure it would be installed w/o a question. The rubber hammer is needed as the pressureplate fits that tight!!!

- - - Updated - - -

Originally Posted by Narlift

I'll paypal you $1000 if you get this completed. That's how confident I am it won't happen. You'd be like..the first one for one thing.

My paypal is richard454 at comcast dot net

**masu3701** · 01-24-2019, 04:18 PM

Originally Posted by Richard454

Here's a cheaper way than getting a hold of a 420G and a E31 flywheel / clutch/ throw-out...

Trans adapter for the M70/73 block

BMW manual gearboxes list:

BMW M20
BMW M50, S50 S5D-250 / ZF-310 S5D-310
BMW M52, S52 E36 M3 5-speed ZF-320 S5D-320
BMW M54, S54 E46 M3 6-speed Getrag 420 226.0.0440.97 / E36 M3 Getrag 420 226.0.0161.91
BMW M57 Diesel (5 speed) GS5-39DZ e39 530D 525D, e46 330D 1434256 ZF 1065401011

http://www.pmcmotorsport.com/44,adap...w-m70-m73.html

This is how I put a 6 speed behind a V12-no adapters were around at the time I did it.

Here's a couple of pics of my BMW auto bellhousing milled down and a plate of 1/2 aluminum drilled to fit the standard GM/Muncie bolt pattern. HOWEVER the T56 uses an integrated bellhousing and this approach won't work w/ it.

Flywheel and clutch-

It's not that tough- just a little tedious to make sure its balanced/centered.

There are several companies selling clutches- most have the bolt dimensions for their clutch on their website- not tough to find. I went w/ a RAM Powergrip 10.5"- the 11" clutch is TOO big for the 13" E31 Flywheel. FWIW- this set up was LESS than $300-pressureplate/disc/TO bearing....or about the same price as JUST a BMW T/O Bearing....

We pulled the dowel pins then surfaced the used BMW flywheel.

Set it up in a rotary mill and proceeded to drill and tap for the pressure plate bolts- six of them.

We then bolted the pressureplate down-and using a small dial indicator( to fit inside the clutch fingers) measured the run out on the machined disc surface. After we got it down to less then a thousandths -we clamped it down.

Then drilled new dowel pins- through the pressure plate. The stock Chevy doesn't use dowel pins- but I didn't fell good about just bolting it down and hoping it was close enough...

After the dowel pins were placed- we marked the pressureplate to assure it would be installed w/o a question. The rubber hammer is needed as the pressureplate fits that tight!!!

- - - Updated - - -

My paypal is richard454 at comcast dot net

Great stuff. Wow!

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**GuildenNL** · 01-26-2019, 08:06 PM

Originally Posted by Richard454

Here's a cheaper way than getting a hold of a 420G and a E31 flywheel / clutch/ throw-out...

Trans adapter for the M70/73 block

BMW manual gearboxes list:

BMW M20
BMW M50, S50 S5D-250 / ZF-310 S5D-310
BMW M52, S52 E36 M3 5-speed ZF-320 S5D-320
BMW M54, S54 E46 M3 6-speed Getrag 420 226.0.0440.97 / E36 M3 Getrag 420 226.0.0161.91
BMW M57 Diesel (5 speed) GS5-39DZ e39 530D 525D, e46 330D 1434256 ZF 1065401011

http://www.pmcmotorsport.com/44,adap...w-m70-m73.html

This is how I put a 6 speed behind a V12-no adapters were around at the time I did it.

Here's a couple of pics of my BMW auto bellhousing milled down and a plate of 1/2 aluminum drilled to fit the standard GM/Muncie bolt pattern. HOWEVER the T56 uses an integrated bellhousing and this approach won't work w/ it.

Flywheel and clutch-

It's not that tough- just a little tedious to make sure its balanced/centered.

There are several companies selling clutches- most have the bolt dimensions for their clutch on their website- not tough to find. I went w/ a RAM Powergrip 10.5"- the 11" clutch is TOO big for the 13" E31 Flywheel. FWIW- this set up was LESS than $300-pressureplate/disc/TO bearing....or about the same price as JUST a BMW T/O Bearing....

We pulled the dowel pins then surfaced the used BMW flywheel.

Set it up in a rotary mill and proceeded to drill and tap for the pressure plate bolts- six of them.

We then bolted the pressureplate down-and using a small dial indicator( to fit inside the clutch fingers) measured the run out on the machined disc surface. After we got it down to less then a thousandths -we clamped it down.

Then drilled new dowel pins- through the pressure plate. The stock Chevy doesn't use dowel pins- but I didn't fell good about just bolting it down and hoping it was close enough...

After the dowel pins were placed- we marked the pressureplate to assure it would be installed w/o a question. The rubber hammer is needed as the pressureplate fits that tight!!!

- - - Updated - - -

My paypal is richard454 at comcast dot net

Narlift is nar to be found. .

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**Narlift** · 01-27-2019, 01:35 AM

I said if HE got it done.
I mean thats cool its been done before though, thought he'd be a first.
Now he's got a guide to follow so he should be all set!