NA 5-SPD Transmission rebuild special tools and stuff...
 

I'm considering completely rebuilding my transmission on my own at home (bearings, synchros, gaskets and seals) and was curious what special tools I would need.
Also looking for any pointers or things to watch out for or be careful of.
I have a real bad tendency of tearing this thing up, I sheared 6 teeth off my first gear the first one and this time I sheared the pin on my 3-4 shift rail. Is there any way I could toughen it up while I have it apart?

the Mazda special tools are pretty simple. the first one is a socket for the main shaft nut, not sure what size it is, 36mm maybe? but the socket is about 2 feet long. i have successfully used a big crescent wrench/chisel before, the nut is supposed to get replaced anyways.

the second special tool is a puller set, and its only really unique because its got extensions so again you can fit over the main shaft. i've used pry bars for this, you are replacing the bearings anyways...

make sure you take lots of pics, notes whatever, there are a LOT of little parts and they ALL need to go back correctly otherwise you get to rebuild the trans again.

I did this, and I would highly reccomend trying to find a mazda transmission manual, it helped a ton and gave more detailed information than the FSM did. I found mine on E-bay, but they are rare.

The nut that calls for the two foot deep well socket was tough. I removed the nut with a chisel, but wanted to install the new one with more finese so I took a socket, cut it in two, and welded in a piece of pipe to turn it into a super deep well, that way I could torque it down properly without resorting to large pliers or adjustable wrenches, seems like they wouldnt fit onto the nut well anyway.

Also try to find the puller you need, I tried to get by with pry bars, but I chipped a tooth on one of the gears. Turns out they are hardened, so they are more brittle than you might think.

And make sure you measure the end play on each shaft as precisely as possible, if you get it wrong you will have problems.

I don't know of any way to toughen it up. Sounds to me that you are banging the hell out of it (or maybe making mega power?).

Proper double clutching and rev matching on down shifts will go a long way toward making it last. I have been tracking my rebuilt tranny for over two years without issues. IMHO proper shifting is becoming a lost art.

To rebuild a transmission you’re going to need a few things beyond the typical sockets, wrenches, and hammers:

1) MOST IMPORTANT TOOL: You need a way to hold the main shaft while you’re working on it. The manual has a special tool for this job. Without this, you’re never going to get the locknuts off and you’re never going to get them torqued back on properly. What I ended up using was an old drive shaft. I cut off the input yoke at the universal joint and what you end up with is the exact same tool as the factory holder: A collar that will slide onto the input and output sides of the main shaft that can be clamped in a vice. Whatever you do, don’t try to clamp the main shaft in the vice without protecting the splines.

2) SECOND most important tool: Once you get down to the rear locknut that holds the 5th gear and reverse stacks, you’re going to need a really long 41mm socket. Like 2 foot long… I ended up buying a deep well 41mm socket from Amazon. I then chopped the top of the socket off and welded in 22” a piece of pipe in the middle. (Sunex 441MD 3/4-Inch Drive Deep 6 Point Metric Impact Socket, 41-Mm - Socket Wrenches - Amazon.com Sunex 441MD 3/4-Inch Drive Deep 6 Point Metric Impact Socket, 41-Mm - Socket Wrenches - Amazon.com )

Beyond that, a decent bearing puller and snap ring tool will get you the rest of the way through a rebuild.

here is a picture of the factory socket in question next to a floor, and a tape measure, and a nut driver.