Gearbox overhall

[WideOpenThrottle]

Can anyone advise on the best workshop manual to buy to overhall an Na gearbox as i would like to do it myself.Cheers.

[SLYDIT]

i think there was a "how to" with specs on miata.net. may have been a link to "trusville mazda" site. not to sure though

[Euen]

There is a posting on Miata.net that gives a lot of helpful information but also refers you to the Miata Enthusiasts Manual. (a lot better than the Haynes one).
http://www.miata.net/garage/tranny_rebuild.html

There are a couple of special tools that you will need. One is a long socket that will reach down the length of the output shaft. From memory it was about 44mm and the length needs to be about 450mm. I ended up buying a 44mm 3/4" drive socket, cutting it in half and welding a length of 40mm pipe between the square drive and the 44mm hex end. It works fine. As the nut you have to undo is torqued to over 150lb ft you will need a long 3/4" strong arm to swing on and a torque wrench with a range that goes well beyond 150 to tighten it back up. (Don't be tempted to use a wrench that only goes to 150 or 160 as you are working at the end of its range and the accuracy is likely to be suspect.)

The other tool was the long bearing puller. I made up a couple of lengths of 25mm steel angle which I used to replace the arms on an "off the shelf" bearing puller from repco.

Good luck. I can't comment on the success or otherwise of a backyard rebuild as the box is still in pieces. I was not happy with some of the clearances and ran out of time so it is sitting in boxes waiting for me to get back to it.

[WideOpenThrottle]

Thanks Euen,maybe i shall get a price from a gearbox reconditioners & go from there.