[manubidegain]

Hey,

My 135 2nd gear synchro is broken and I need to make a replacement.

Do you know if I can make a replacement with this gs6-45bz coming from a m3 ?

26K MILES 15-18 BMW F80 F82 F87 M3 S55 GS6-45BZ MANUAL TRANSMISSION GEARBOX MT (eBay description)

I will buy a flywheel and a clutch too:


15-20 BMW F80 F82 F83 F87 M2 M3 M4 MANUAL CLUTCH DOUBLE MASS STEERING WHEEL ORIGINAL EQUIPMENT MANUFACTURER 51k (eBay description)

Thank you !!!

[mc2226]

Hi, any news on this one?
I'm planning to put that gearbox in my M135i aswell. Except that mine is from the F87 M2.

Two problems came into my mind (unfortunately after i have bought the M2 gearbox):
1) the neutral switch on the M135i gearbox only detects neutral for start/stop automatic, while on the M2 gearbox it detects neutral and the gears (at least reverse gear) which brings me to
2) the reverse gear switch on the M135i is located on the rear left of the gearbox, where the M2 box doesn't have a switch but only the same casted piece on it. The question is: is the mechanism that activates the reverse gear switch still inside the M2 gearbox, so that a drilled hole will do the trick?

3) related to 1): the holes for fixing the neutral switch (M135) or two channel switch (M2) are completely different, which means, that you can't simply put the M135i sensor on the M2 gearbox. But will the M2 Sensor work with the M135i? (the connector housings of those sensors are also different)

Must have a reason, why nobody has done that swap by now?

Regards,
Ben

[manubidegain]

Didn’t have any new yet, I’m still having the same problem, is super annoying Zf or bmw doesn’t sell replacements parts for this gearbox even knowing the 135 gearbox synchros are trash 😡

[mc2226]

yeah, it's super annoying.. but anyway - i'm making it my winter project and will share the process..

first step is decoding the 2-channel gear and neutral sensor signal, to switch on a relais for the reverse gear switch and telling the ecu when the gearbox is in neutral.
from that on it should be straight forward..

...hopefully...

[manubidegain]

I saw a new saying the new Toyota Supra will have a tweaked gs6x45bz. Do you think Toyota will provide those pieces ?

I already talk with Zf and they says is on bmw to provide this or not.

[mc2226]

even if they provide those parts - who can tell if they fit in our transmissions? guess someone will have to try it then..

[mc2226]

short interim report from my side:

i got both sensors decoded, but that isn't the biggest problem.
It seems that in the 1 series the N55 has a 8-bolt twin mass flywheel, so you can't use the M2/M3 twin disk clutch you would need, as the bell housing is about 3cm longer. It seems, that the M3 G80 twin mass flywheel and clutch could potentially fit.

But bofere i try that, i am going to swap the bell housing from the old M135i tranny onto the M2. If that works, the only thing that has to be done is to drill a hole and cut a thread for the reverse light switch.

I'll keep you updated

[mc2226]

So good news on the swap: I've been driving from the workshop to the garage today!

The swapping of the bellhousings was easy going. If you care about the start/stop automatic, you have to put the old magnet onnthe shift shaft onto the new one.

Other than that, a hole has to be drilled and an M12x1,5 mm thread for the reverse gear switch has to be cut.

Happy switching

[-Eidos]

Originally Posted by mc2226

So good news on the swap: I've been driving from the workshop to the garage today!

The swapping of the bellhousings was easy going. If you care about the start/stop automatic, you have to put the old magnet onnthe shift shaft onto the new one.

Other than that, a hole has to be drilled and an M12x1,5 mm thread for the reverse gear switch has to be cut.

Happy switching

PM'd

[xquatch]

Originally Posted by mc2226

first step is decoding the 2-channel gear and neutral sensor signal, to switch on a relais for the reverse gear switch and telling the ecu when the gearbox is in neutral

If the mechanical "Reverse Switch" isn't used on the new transmission, then does the "Gear Sensor" provide that signal? Is that what you mean by decoding the 2-channel sensor? Or did you actually drill out the hole for the mechanical switch and install it?

And if you just used the "Gear Sensor" then did you also have to modify the "Reverse Switch" 2-wire plug to accommodate the 3-wire 2-channel signal?

[mc2226]

Originally Posted by xquatch

If the mechanical "Reverse Switch" isn't used on the new transmission, then does the "Gear Sensor" provide that signal? Is that what you mean by decoding the 2-channle sensor? Or did you actually drill out the hole for the mechanical switch and install it?

And if you just used the "Gear Sensor" then did you also have to modify the "Reverse Switch" 2-wire plug to accommodate the 3-wire 2-channel signal?

i used the reverse switch on the new transmission and drilled a hole for it, as i completely changed the bell housings and therefore the 2-channel sensor can'r be used anymore. The 3-wire 2 channel sensor is of no relevance for this solution.

But if you can use the complete M2 gearbox, the 2-channel sensor can be decoded and the mechanical reverse switch can be switched by a relay of a microcomputer for instance.