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Question on Tranny Swaps

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Old Mar 30, 2006 | 10:51 AM
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1990Rx7Gtu's Avatar
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Question on Tranny Swaps

Alright, I hear that I could do a tranny swap on a 90' gtu.

I dont know if this is true or not, but I guess a Miata tranny would work for it??

My problem is that the tranny now doesnt go into 1st, and 2nd gear is going too. So yeah, just thinking of tossin the tranny and gettin a different one.

I dont know much about cars, but yeah, thats why im asking you guys lol.

Also, anyone know prices on getting any type of tranny that would fit?
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Old Mar 30, 2006 | 11:59 AM
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the Miata GEARS will fit, but not to my knowledge will the tranny itself bolt up at all......

Check the forsale sections in your area, N/A trannies are a dime a dozen....
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Old Mar 30, 2006 | 12:29 PM
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the Miata input shaft is wrong too as I recall.
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Old Mar 30, 2006 | 01:25 PM
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Originally Posted by Icemark
the Miata input shaft is wrong too as I recall.
you would have to take both of the imput shafts to a mechinist and have the miata imput shaft milled down to look exactly like the 7's input shaft. and the bell housing wont match up with the engine so you would have to gut both tranny's and put the miata gears in the 7's tranny housing.
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Old Mar 30, 2006 | 01:33 PM
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Good used trannys run $200-400.
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Old Mar 30, 2006 | 01:41 PM
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when i did my miata gear swap, i had the imput shaft resplined. the miata gears fit into the fc case nicely. check the link in my sig for more info on the swap, or pm me. miata trannies can be got for very cheap
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Old Mar 30, 2006 | 02:16 PM
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From: indiana
Originally Posted by RXgirl7
when i did my miata gear swap, i had the imput shaft resplined. the miata gears fit into the fc case nicely. check the link in my sig for more info on the swap, or pm me. miata trannies can be got for very cheap
she's the one to talk to cause she is one of the few that actually did it
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Old Mar 30, 2006 | 03:34 PM
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Hmmm idk, that seems like it would take a lot of work.

And I really dont want to put a lot of money into this car... I dont know, I'll look into this more.
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Old Mar 30, 2006 | 03:35 PM
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From: indiana
now are you wanting a stronger tranny or do you want the gear ratios to be closer
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Old Mar 30, 2006 | 03:51 PM
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See, what I would want would be to use a the Miata 6 speed, and just have a way high 6 th gear... you know something like a .605 or so. So you'd have 4th at 1:1, 5th at .781 6th at .605

Then I can see making the swap.

But the sticking of the 5 speed or 6 speed just getting a little closer ratio... well whats the point??? Its not like the rotary only makes power in the 2.5 K to 4K rpm range like most piston motors.
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Old Mar 30, 2006 | 04:15 PM
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Originally Posted by Icemark
See, what I would want would be to use a the Miata 6 speed, and just have a way high 6 th gear... you know something like a .605 or so. So you'd have 4th at 1:1, 5th at .781 6th at .605

Then I can see making the swap.

But the sticking of the 5 speed or 6 speed just getting a little closer ratio... well whats the point??? Its not like the rotary only makes power in the 2.5 K to 4K rpm range like most piston motors.
id love to put a miata six speed in here someday
for my situation, swapping the miata 5 speed in has been a huge difference and advantage. on-track, i am able to shift right into my powerband, wheras before, with the stock tranny, i was shifting in before the power came on, and right as the aux ports were opening up. 5th gear is alot less of a throw-away(has acceleration)although top-speed is reduced. 1st gear is VERY tall, hence why i would NOT reccomend this swap to anyone interested in drag racing.
yes, its more involved than putting in a stock or turbo tranny, yes you have to alter the imput shaft. its a personal choice. for me, it was the right choice. everyone who has driven it seems to like it.
if there is a mazfest again this year, everyone is welcome to have a ride!
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Old Mar 30, 2006 | 04:21 PM
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From: Rohnert Park CA
So did they change the diameter (and splines) of the input shaft or just the length???

Your thread on it (now in the archive) didn't really cover that.
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Old Mar 30, 2006 | 04:28 PM
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You can bolt up a RX8 transmission if you feel so inclined. If you use TII parts (flywheel, driveshaft etc.) it will bolt right up. You will have to modify a crossmember, I think the shifter postion is like around an inch difference, and you won't have a speedo.
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Old Mar 30, 2006 | 04:30 PM
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Originally Posted by flamin-roids
You can bolt up a RX8 transmission if you feel so inclined. If you use TII parts (flywheel, driveshaft etc.) it will bolt right up. You will have to modify a crossmember, I think the shifter postion is like around an inch difference, and you won't have a speedo.
see again no advantage for me and my driving style... top gear is too simular
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Old Mar 30, 2006 | 04:34 PM
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From: Manhattan Beach, CA
Originally Posted by Icemark
So did they change the diameter (and splines) of the input shaft or just the length???

Your thread on it (now in the archive) didn't really cover that.
the shaft was resplined and slightly shortened.
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