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2001 Miata SE
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571 Posts
Discussion Starter · #1 ·
I need to replace my transmission, and I would like to install a legacy GT 5-speed.

Do I need to change axles, clutch, flywheel, or rear diff? What other parts won't be compatable?

I know I'll need to get an electronic spedometer correcter, but what else, in addition to the transmission?

So basically an all inclusive parts-list. I couldn't find this information.

Thanks.
 

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opendeck251+stiInternals
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483 Posts
You might need the front axles, IIRC, the newer tranny's use axles that are male at both ends of the axle. Tranny should bolt up to your current mount. You will need the clutch and flywheel to go with the tranny. You should be able to use your car's clutch master cyl. and lines and just plumb it into the GT's slave cylinder, maybe, IDK if the GT is push or pull style.

If the axle ratio's are different you will need the GT's rear diff, or a diff of similar ratio. I don't think it HAS to be the GT's diff. Stock driveshaft will work, since the GT tranny is the same size. As far as your speedo goes, just take your's out and put it into the GT tranny.

I think that should be all you need, feel free to correct my wrongs if you find conflicting info.


~Josh~
 

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2001 Miata SE
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571 Posts
Discussion Starter · #4 ·
Why do I need the clutch and flywheel?

What about the starter?

I might be getting a 2008 LGT 5speed, diff, and all four axles from a member on legacygt.com, but he doesn't have the clutch and flywheel. Another member has a clutch and flywheel, but it's off of a 2005 LGT with 80,000 ish miles.

Would it be worth it to get the clutch and flywheel from the other member? I currently have a exedy stage 1 (5000 miles on 1/4 throttle) and an exedy LW flywheel with 5000 miles on it as well. I really don't want to deal with finding a LW flywheel for the legacy gt trans. It's most likely much more expensive...
 

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yep. you heard me.
‘18 E63s AMG wagon & 10 Subarus
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6,473 Posts
you need to open up the transmission and insert the speed sensor gear from an older transmission. and you need different axles or while you are in the transmission, insert the axle stubs from an older male-style transmission (legacy gt 05+ uses female style transmission with male style axles)

also you will need the clutch and flywheel from the turbo car, and if you have a 95 impreza with cable clutch, you will probably want to convert to hydraulic clutch pedal box and master cylinder.

http://www.rs25.com/forums/f8/t163493-famous-lgt-transmission-swap.html
05' LGT trans swap - Speedo Gear Problem - NASIOC
GC8 2.5rs w/05 LGT trans, What clutch/fly? - NASIOC
http://www.rs25.com/forums/f8/t161207-lgt-transmission-swap-questions.html
 

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2001 Miata SE
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571 Posts
Discussion Starter · #6 ·
Will I need the 2008 LGT starter as well? I'm still confused as to why I need the LGT clutch and flywheel.

If I use my 2001 2.5rs starter, won't the 2001 2.5rs flywheel work?

The 2008 LGT trans has a push type clutch, just like my 2.5rs trans.

If I don't change the speedo sensor gear, will my speedometer work, and just display the incorrect speed?

I will be using LGT axles, so I won't need to worry about that axle stub thing.
 

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yep. you heard me.
‘18 E63s AMG wagon & 10 Subarus
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6,473 Posts
i guess you dont need to use the LGT/turbo clutch and flywheel though it would be recommended unless you already have a higher-rated clutch in there.

the LGT transmission uses ABS signals to calculated speed, so it doesnt have a speed sensor gear in the transmission. without it, any car that needs a transmission speed sensor (all impreza up through 07 and any legacy pre-05) wont have that signal and will probably go into limp mode (as well as your speedo not working)
 

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2001 Miata SE
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571 Posts
Discussion Starter · #8 ·
I see. So even after I replace that speedo gear thing (which honestly seems like a large cost mistake waiting to happen) I still might not have a correct speed, since my ABS sensors are currently mismatched and the ABS isn't working.

In your opinion, should I get the metal speedo gear, or the plastic one? I'm thinking metal, since even the plastic one is pretty expensive for a little gear.

Thanks for your responses, by the way.
 
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