1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

12a N/A T2 tranny help

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Old 10-29-10, 06:07 PM
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12a N/A T2 tranny help

I searched for a good walkthrough but have not found one.
I know how to modify the tailshaft and shifter to fit into the FB also the tranny mount is easy.

What i do need is help with the bell housing will it bolt up or do i need to swap that out also?

also there is a drifshaft place that can make the new shaft for like 180$ so im coverd there.

anyone done this and have any tips or tricks.
Old 10-29-10, 06:19 PM
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The bell housing is removable only on the ribcase trannys. The TII and pre-7 ones like the REPU had. You'll need a TII clutch, lightweight flywheel TII, (240 mm), and appropriate counterweight for your 12A.
Old 10-29-10, 06:35 PM
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so the t2 tranny will bolt up to the 12a and were would i get the counter weight for the swap.
Old 10-30-10, 02:55 AM
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What year are your rotors? Mazdatrix no longer sells '83-'85 rear counterweights. '79-82' still available.
Old 10-30-10, 03:29 AM
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the egine is all 83 cant i just put the 87-88 counterweight on?
Old 10-30-10, 05:16 AM
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Counter weight must match the rotors. Oh, and you need the TII starter also.
Old 10-30-10, 03:05 PM
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i was going to say why would i change the counterwieght all im doing is useing a t2 tranny on my 12a
Old 10-31-10, 02:11 AM
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i got the tranny ill do a nice write up with pictures on hot to mod the shift link and such
Old 10-31-10, 02:17 AM
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Why are you changing to the T2 on an NA 12a? Did your old gearbox break and the T2 was easier to get a hold of? You going turbo at some stage? Reason i'm asking is because its a lot of trouble you're going to for a gearbox you don't really need that's actually just going to slow you down with the longer ratios.
Old 10-31-10, 07:39 AM
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https://www.rx7club.com/old-school-other-rotary-63/going-old-skool-got-repu-653888/page2/

This might help a bit, starting at post #32. You only need to move yours about an inch forward.
Old 10-31-10, 04:14 PM
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12a stripped carb
racing beat roadrace header
electric fan
stage 3 kiwi clutch set
Nitto Nt 555R sticky tires
4.11 pinion gears
solid rear tourqe bars

This seems to destroy my transmission i need the t2 tranny to handel the extra jult from my components.
Old 10-31-10, 08:49 PM
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get a rx4 bell housing.....this way all u have to do iz bolt on bell housing to the turbo2 box......u need modified the starter hole and custom drive shaft.... that it........
Old 10-31-10, 09:08 PM
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that would cost more then the transmission
Old 10-31-10, 09:35 PM
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look around.....i got one for 86 bucks on ebay. you r going to spend $$$$$ no matter what......good luck
Old 10-31-10, 11:46 PM
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Light weight flywheel, counter weight and TII clutch can easily set you back $400 being cheap, $800 if going all new parts.
Old 11-01-10, 12:00 AM
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im not worried about getting the flywheel and clutch and counter weight, i have not tried to mount the tranny on the back plate so if it will bolt to the 12a then ill buy all the stuff.
Old 11-01-10, 11:07 PM
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so with the rx4 housing you can use a 12a clutch/flywheel?
im thinking about going with the tII i have ruined 3 trannys and one was just rebuilt. will the tII hold up to 400rwhp?
Old 11-02-10, 02:23 AM
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The TII tranny has been known to hold 600+ hp. It's the torque that tears **** up.
Old 11-02-10, 03:52 PM
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nice!! thanks i think that would be a better option than the heavier mustang t5 or an outrageously expensive supra tranny thanks!!
Old 11-02-10, 10:21 PM
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thats why i needed the t2 ranny was the intial tourqe of my engine and other i have a trow in tranny for it for now im just starting this to be ready for when this one breaks.
Old 11-03-10, 03:39 AM
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ok stop if im wrong this is what i have concluded

My 12a engine:
1983 12a flywheel and matching counterweight.

in order for me to put get the t2 tranny in i need to get a t2 flywheel and clutch only i DO NOT need to change the counterweight.

the tailshaft shift link is easy so lets not worry about that and the drivehaft is easy also.
Old 11-03-10, 04:51 PM
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Originally Posted by Man_in_black49464
ok stop if im wrong this is what i have concluded

My 12a engine:
1983 12a flywheel and matching counterweight.

in order for me to put get the t2 tranny in i need to get a t2 flywheel and clutch only i DO NOT need to change the counterweight.

the tailshaft shift link is easy so lets not worry about that and the drivehaft is easy also.
Yes you DO need to change the counter weight. You will need an after market flywheel which will require you to buy the rear counter weight for the '83 12a rotors.
Old 11-03-10, 08:25 PM
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if it needs to match my engine rotors wouldnt the weight i have on the 12a now stay there?

Why would i need to buy a new counterweight is it to match the new lightend flywheel?
Old 11-04-10, 03:11 AM
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All stock flywheels have the countering weight built into them to match the weight of the rotors in that particular engine. Your flywheel/engine/tranny takes a 225 mm clutch, the TII flywheel and clutch are 240 mm. The stock TII flywheel is weighted to match the rotors for the Series of the car, (S4 or S5). The TII tranny needs the larger flywheel for the starter to engage and the TII tranny takes a different starter than the NA trannys. Lightweight flywheels have a neutral balance meaning a counterweight to match the rotors in the engine is needed.

I can't seem to find the flywheel guide that was on MazdaTrix's or Racing Beat's website. It showed all the different flywheels along with the weights and part #s for the different years and engines. Mariah does have a flywheel weight comparison table.

Racing Beat and Mariah Motorsports both sell the 83-85 12A counterweight or you can try and find a used one for sale. The automatic transmission cars have the same counterweight that's needed for the lightweight flywheels. Why, because the flexplate, (flywheel in an auto tranny), has a neutral balance and needs to be balanced to the rotors.
Old 11-04-10, 04:42 AM
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You go to pay to play bro...You have to change the flywheel, then install a new clutch, and you have to use the rx4 bell housing...

Check my thread in my sig, i have details in there...i have done this swap countless times bro, its easy...

I went with the 4 puck springless clutch...i love it...


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