Miata Transmission

B

bulldoezr

New member
I picked up a free transmission with a broken syncro that I want to use in my 91 Miata street car. The donor was free and the person I got it from had no idea what it came out of. My understanding is that a 1.8 transmission will work in a 1.6, but how do I tell what my donor is? Is there a difference between the 1.6 and 1.8 transmission? It seems to be the question asked of me when ordering parts. I was told this transmission was grinding going in to 2nd which is what my street car is doing. My car is still drivable so I want to repair the donor first. Any help is greatly appreciated.
 
all miata transmissions 90-05 will bolt up. the important differences were on the synchros/clutch hubs/etc. there should be a VIN plate on the side of the trans you can use to figure out what year, otherwise i don't know.
 
Unless you're are planning on doing the rebuild you could be looking at $900+

New, late style trans (it will fit and is legal) are $1200+ .

You can find a good used one for around $300 and if you use good fluid can get 2years or more racing.
 
Since this is for my street car, I am going to do the work myself. The only thing I can see wrong is a broken syncro ring, but I'm not sure what to do for parts.
 
You mean a socket thats about 2 feet long? Yes, I am aware and have already made one to get the nut loose. It came apart without too many special tools other than the socket. Snap ring pliers, a bearing puller, and a 12mm socket wrench seemed to work.

Thank you xr4racer. What part of the serial number tells the year?
 
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"The VIN is JM1NA353XR0505368"

The tenth digit of the VIN will tell you the year. "A" is a 1980, "B" is a 1981 and so on skipping "Q". In Y2K, it went to numbers "0" for 2000. I think for the 2011 models we are back to letters again.

Good luck with the rebuild.
cheers
dave parker
 
Just an FYI, they tend to commonly fail;

Block rings
Syncro keys
Forks
Rail ends

You may want to upgrade to the newer 2nd gear syncro, but this require lots of $.

All of the parts are pricy if you pay full retail from the dealer. If you need I have a spread sheet with the common part #'s. I have done about a dozen in the last year alone.
 
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