What trans do you run with an M20?

[ClayW]

I've heard E21 323, but I don't even know where to start looking for one of those.

Is it a clearance issue with the front of the motor? If so, couldn't you just cut more out of the front to fit a regular (320) E21 5 spd?

Thanks in advance.

[JohnN]

M10 tranny variants (including ones from the E21 4 bangers) will not fit because the different bolt pattern.

The tranny that came with the M20 in the E30 is said to fit if you're willing to cut the tranny tunnel and make it much wider and deeper (not for the faint of heart).

Good luck finding a tranny, they are available, just not very common.

Regards

John N

[MrNvgtr]

Getrag 260. I'm not sure what else will fit.

[evanc]

I talked to Ben Thongsai a few years ago and this is what he said, "If you can live without a speedo, a '91 318i/is trans will work. If you want to get down and dirty, you can mate the front housing of the '91 318 trans with the rear of a '83 320i trans and have a trans that will bolt to the M20 as well as have a speedo drive. There's a slight mounting angle difference (10 degrees) but it's not too bad." As others have said the Getrag 260s are not that common, so this might be a more immediate solution if you can't wait around years for one to turn up like I did. I literally waited, saving money and then boom all of it was available!

Good luck. If I come across one I'll shoot you an email.

Evan

[ClayW]

(nt)

[MrNvgtr]

The Getrag 260 is very common. I'm not sure why you looked so long because they were installed on millions of e30 325 cars. I picked one up not too long ago and I remember there being endless amounts of them for sale on the boards. Between all the cars being parted out and all the e30 guys going twin cam, he won't have any trouble finding one.

[ClayW]

Quick questions:

Does the M20 not bolt up to the Getrag 245 from an E21 320i?

The Getrag 260 from an E30 is also an option, but I have to cut up my trans tunnel?

What's the name of the 5 spd/overdrive trans from an E21 323i?

Thanks, guys. You've been really helpful.

[PSloan]

Clay, I think doug punches has a 4 speed from a 323. He's in fort worth. I'm not sure whether or not its for sale, but i guess you can ask or maybe he will chime in.

[ClayW]

(nt)

[evanc]

I'm just passing along information that I've gathered over the years about doing the M20 conversion and sharing what I've learned. Ben Thongsai is a very knowledgeable BMW guy and I wanted to offer another option for Clay. With all those Getrag 260s out there Clay you shouldn't have a problem. Good Luck. Look forward to following your progress with your conversion.

[Guest Anonymous]

The Gatrag 260 from a 325i will fit in there if you cut the center hump and enlarge it. But you lose the speedo, because the 325i ran the speedo to the rear diff, not the trans. You can run the 260 and then buy a fancy new speedo that runs on Hall Effect. That is, you would mount (epoxy) magnets to drive shaft, and put the new speedo sensor there to read rotations off the magnets. I think you just calibrate the speedo so it knows how many feet traveled per rotation. This is what i am currently doing to : )

[Guest Anonymous]

Quick trans run down:

Stock 2002 4 spd: Getrag 232

Stock 320i/323i 4spd: Getrag 242, but the bellhousing is different depending on which motor it is attached to

E21 320i 5spd: Getrag 245 for 80-early 83 models

E21 323i 5spd: Getrag 245, but different bellhousing from the 320i trans, this is the trans most people want for an M20 conversion, it's small enough to fit in the 2002 tunnel, is a 5 speed, and has a speedo drive

E21 320i 5spd: Getrag 240 for the late 83 models, has the 2 piece case

E30 318i 84-85: Getrag 240 same as '83 320i but with no speedo drive and dual rear trans mounts (note that some '84-'85 318i's came with a ZF trans that is completely different)

E30 318i/is '91: Getrag 240 but with a bellhousing that fits the M20/M50/M42 motors, no speedo drive with dual rear mounts. You can mix and match this trans with the '83 320i trans and get a Getrag 240 that bolts to an M20/M42 and has a speedo drive.

E30 325/e/i/is: Getrag 260, bigger than any of the above transmissions, no speedo drive. Doesn't fit the 2002 tunnel very well without some "help." E28 528e '83-'88 also used this transmission, as well as '89-'90 E34 525i.

E28 528e '82 only: Getrag 265, bigger yet than the Getrag 260, but near indestructible under most usage, detachable bellhousing, has a provision for a speedo drive, will bolt up to an M20/M50/M42, good luck getting it to fit in an '02 tunnel without major surgery. (unless you have an automatic shell, then it's more likely)