Bummer! the guy on Miata net Garage said actual bolt size of NB 2002 trans. is 23mm and he used a 7/8 inch "box" spanner.Maybe that fits but I'd rather use a Ring spanner.
Quote......"After studying the above article I set about changing the lubes in my 2002 NB 6-speed manual transmission and differential. I found an error in the How To that will hinder everyone who follows it if their transmissions are like mine.
The article says to use a ratchet and socket, but mine wouldn't fit between the transmission and the exhaust pipe. It also says one plug is 23mm and the other 24mm. On my transmission, BOTH are 23mm, and my sockets go from 22mm to 24mm. But a 7/8" box wrench fits fine. In fact, it's the perfect tool for getting to the refill plug around the curve of the side of the transmission. Every set of box wrenches I've seen goes to 7/8" so it should be the tool of choice for this job, not 23mm and 24mm sockets with a ratchet. I set out to buy short 23mm and 24mm sockets (the article warns there isn't much room), but couldn't find them, so others will want to know they are not needed."
Far as I know, only one Diff. bolt is said to be 23mm..
confusing
Anyway I'll get the Redline MT90 in a couple of days and go to it then.....