Transmission advice

[417m3]

Looking for some transmission advice.....

Background on car:
2004 e46 m3
6766 precision turbo
Tuned on e85
Roughly 600 horse/640 lbs torque
6 speed manual getrag 420

I ended up putting a clutchmasters fx850 like 3 weeks ago in it.

The stock getrag 420 was the next to go. 3rd gear synchro shot. Lots of flakes when we drained the fluid. As many of you prob know, the getrags are put together under certain heat specs so they are impossible to find parts for. Nobody will crack one open and try to fix them.

Here are my options as I see them-

Find a used getrag 6 speed.
Pros- cheapest option, can use my new clutch
Cons- same thing will happen sooner or later

Find a used ZF 6 speed.
Pros- allegedly holds up a little better, less abused, driven with less hp prior
Cons- can’t use new clutch/flywheel
Same thing will still prob happen sooner or later

Find a used SMG and convert it to manual
Pros- should be less beat up, can use current clutch
Cons- same thing will prob happen sooner or later

Samsonas dog box
Pros- bad ass. Fast. Can handle the power.
Cons- $7k for gearset alone, would need to find different core, different clutch, can’t afford it, wife would divorce me


Call me crazy option.....

Th400 auto swap
Found a guy that has the adaptor kit to bolt it up to S54.
Pros- bullet proof, cheaper to fix, will leave room for more power, fastest option on the strip, can sell clutch to offset some costs
Cons- going from a 6 spd to an auto, not as daily driver friendly, would need some fab work, would need driveshaft and torque converter, also kind of against code to be putting gm tranny in a bimmer. Karma.


If I’m missing any options, please fill me in. I’ve been scouring the internet the last week. I appreciate any feedback. Thanks!

[yukon101]

I don't see a reason not to use another 420G, they are very stoutly built transmissions and are used in many drag cars. They are also used in a lot of really high power MK4 supras. That's why I am running one in my E32 currently.

[Honolulu]

As time passes, you may have to take the first available trans you can find. Respect to Yukon101's opinion above. Just because you blew your trans, doesn't mean the next one will go the same way.

Two of your options have you re-using your clutch, and one has you selling it. Your somewhat-new clutch is an asset rather than a liability.

As for your wife's opinions, well, you brought that on yourself when you boosted the engine then blew the trans. Pay the piper, but keep her onboard.

[FercompSamsonas]

For Samsonas, will be haply to give info and pricing. The H Pattern with case, shifter, adapter plate, input shaft is $7,600 in total (shipping from Charlotte, no out of state tax). Email inga@samsonas.com, will be happy to send info 👍