cookfc3s

Ok I have heard and seen that it is possible to swap miata gears in a fc transmission and im wondering what year miata transmission I need for the gears and what all alse I need to doto make this work. My rx7 is a 91 non turbo and I want to do this cause my gears and bearing are junk and id rather do the miata gear swap then try and find stock rx7 gears and bearings.

diabolical1

iTrader: (3)

welcome to the board.

i will assume that you're not interested in simply replacing the transmission, which would overall likely be cheaper. is that correct?

that said, from what i've read on the subject, it sounds like any Gen I or Gen II Miata 5-speed should work. they are basically Type M trannies inside a different case. aside from the gearset, you will need to grind a certain amount off the input shaft (obviously, keeping the general bevel/shape). i can't remember the amount, and since there is quite a detailed thread on it, i won't venture to guess. you can just look it up.

you will need to buy (or make) a few special tools, but aside from that, it's simply a matter of swapping gearsets and performing a general tranny rebuild (seals, gaskets, etc.)

cookfc3s

Yea I was going to get another transmission for my 91 rx7 but I live in IL and they are a pain to find and I have tried ebay but only found older transmission and I am haveing a hard time find parts also. I had some people say to just do the miata gear swap since the transmission are easyer to find. But yea right now I already have mine apart because the input shaft has a cut in it from the main bearing taking a crap and making it spin on the side of the pilot bearing which is destroyed and also the gears lock in neutral but not the others. The kid who use to own it ran the car with no fluid in the case.

heynoman

iTrader: (5)

where in Illinois are you I may have a shaft around here somewhere

zak rabbit

Really, all you need is to swap the front and rear housings of your trans onto the Miata gear set after modifying the Miata's input shaft. Look on Mazdatrix's website for the detailed modification necessary.

cookfc3s

La fayette, il up buy kewanee. We finished pulling the trans apart to see what was all wrong come to find out I just need a new input shaft and synchronizers

Wheelspin

I'm not up on the gear swapping, but I can tell you the '94-'05 5-spd trannies are the same, and are good for up to 250 whp or so before they start coming apart. The 6-spd is a stronger tranny, but not sure what the compatibility is between it and the RX's 5 spd box. The MazdaSpeed transmissions are supposedly case-hardened gears, but it's been debated on the Miata forums ad nauseum whether it's really any stronger than the non-turbo trans. Good luck on the gear swapping.

diabolical1

iTrader: (3)

Guys, please. I understand helping a fellow forum member out with parts, but let's please keep the actual details out of the threads in this section. I deleted the offending posts and offer this post as a warning. I will leave the thread open for any other posts on the technical matter at hand, but let's keep in on that subject only OR ... if the OP has resolved his issues and would like, I can close it.

heynoman

iTrader: (5)

Sorry about that I think OP resolved his issue plus you guys explains the jist of it already