Two things:

Yes you do need a lot of special tools -- gauges, snap ring pliers,
micrometers, etc.

Also, you need to be really good at feeling the proper play in a
bearing, setting preloads, etc.

If you have the tools, and you have a multitude of automotive
experience, you could probably do it. I've been working on cars for
half of my life and I still don't feel confident enough to tackle a
transmission.