I am looking for a reverse gear and it's hub in good condition. If you have the assembled gearshaft & counter shaft I would also like to get it

Here is a few picture of what I am looking for




Here is what it should not look like (look at the dog teeth)

 

I found one, turns out that RX8 6 speed gearbox use the exact same part. They are also pretty cheap (I bought a complete gearbox for $80)

 

So what is the degree of difficulty to get to, replace and reassemble it from a DIY perspective?

 

If you're careful and clean, not terribly difficult. I recently disassembled one just to reseal the cases, which have a tendency to leak. You have to disassemble the reverse/6th gear mechanism to remove the middle case. As with any transmission reassembly, I can't stress enough the importance of running it through the gears after assembling it. It won't magically "fix" itself in the car. Mine for instance wouldn't go in reverse. Turns out the detent shaft has a small notch indicating which way it needs to face, and I had it reversed from where it should be. Easy fix, but best to find those on the bench vs. in the car.