I was looking thru the competition parts list at Mazdacomp a few weeks ago and found they had these parts listed:
1st clutch hub set
3rd clutch hub set
3rd gear

with "99+ RX-7" as the comment. I called to figure out what the difference was compared to the 93-98 parts. This is what I was told:
- The 1st gear in 99+'s are single cone synchro instead of double and use the same synchro as the Miata. Going single-cone in 1st instead of the original double-cone sounds like a downgrade.
- The 3rd gear in 99+'s use the same synchro (still double cone) as the miata.

Anyone torn down a 99+ tranny that can confirm the differences? Anyone have some late-model Miata synchros to know whether there might actually be an benefit that isn't obvious?

Dave

 

Dave,

did you ever find anything about the differences ? One of our forum members who imports J-SPEC RX7 parts, charges a premium for the '99+ trannys . . .

:-) neil

 

I have not learned more than this.

99+ are getting good prices I assume for mileage and the 5th ratio. They should also have the updated select spindle and 5th synchro.

David