We are building synchros for the E46 M3 transmission. The first major obstacle was getting the transmission apart. Here's a quick video showing the transmission and how the synchros work.
It will be nice to have replacement synchro's available... are they expected to match OEM specs or is your aim to improve feel or longevity? Having rebuilt my share of gearboxes, I'd be interested to learn what it is about the Getrag that makes disassembly so difficult. Care to share?
I will know more about the coatings soon. Our goal is to atleast match OEM specs. Getting the transmission apart required us to build several very specialized very heavy duty tools. I can't go into more details than that.
Chris.
dcf said:
Awesome work. The SMG trans in my dedicated track car (road race, so 2-3-4, 4-3-2 is what matters in my world) lost the 3rd gear (and possibly 4th gear) synchro and over the winter off season I have had to swap in a salvage unit since, as you say, no one really works on these or has parts for them. No one I know has ever had this happen to an SMG on a n/a car, but it happened to mine. If you guys develop any products for the gearbox internals, or need any parts for testing, inspection or fabrication, please let me know.
Did you disassemble it on a "hot bench" or at an elevated temperature? I have heard they are assembled by Getrag at the equiv. of operating temperature, which is part of why they are so hard to work on (and why no one really does). That may be why it would not come apart, as at room temperature the tolerances are different and the press fits are tighter.
I'd love to see your transmission. We blew one up while tracking our HPF M3 as well. I think we will have plenty of spare parts from these. Those transmissions really do not want to come apart. So we had to design some pretty hard core tools to do it.
Awesome work. The SMG trans in my dedicated track car (road race, so 2-3-4, 4-3-2 is what matters in my world) lost the 3rd gear (and possibly 4th gear) synchro and over the winter off season I have had to swap in a salvage unit since, as you say, no one really works on these or has parts for them. No one I know has ever had this happen to an SMG on a n/a car, but it happened to mine. If you guys develop any products for the gearbox internals, or need any parts for testing, inspection or fabrication, please let me know.
Did you disassemble it on a "hot bench" or at an elevated temperature? I have heard they are assembled by Getrag at the equiv. of operating temperature, which is part of why they are so hard to work on (and why no one really does). That may be why it would not come apart, as at room temperature the tolerances are different and the press fits are tighter.
We finally did find a company that can build the syncros for us. It would just be a huge investment and there may be patent issues. So we're not going to go down that road. We can rebuild transmissions and replace them with parts from other transmissions, but we aren't going to be developing our own parts for them.
Thanks for the update Chris. Its a shame you guys will not be doing this but its very understandable that the returns might not be there on the investment. HPF FTW
Chris, how much would a rebuild be? I have a 2002 m3 smg. I had aa sc for about a month and about 140k on the tranny. Ian not exactly sure what the problem was but the shop told me it would not shift into gear after replacing the spring on the housing. The dealer diagnosed it as a tranny issue. It was causing my engine to die in heavy stop and go traffic. I would guess it is the syncros but I am no expert. Anyway I bought a brand new tranny but kept my old one. I was thinking of getting the bad one rebuilt. Thanks. Great video as well!
Both transmissions may be fine. It could very easily be an SMG issue or the transmission not synched properly. Anyway, we aren't rebuilding these transmissions although we could. We typically just buy used ones.
Wow! So this just really scared me! I decided not to buy a SMG M3 because I don't want to deal with SMG failures but now you're saying basically no one can rebuild even the manuals!?
Amazing that there are so many M3s out there but no way to fix a tranny besides replace the whole thing :thumbdwn:
Its awesome that at least you guys are looking into it and attempting to do something about it! :thumbsup:
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