'02 PT Cruiser Manual trans- won't go into gear

[win_daddy]

It's a NON-turbo, New Process A578 gearbox (same as the Neon I think). Linkage and bushings are all good. Shift lever going into the top of the trans was getting loose- it continued to drive for about a day, now it won't go into gear at all.
The same thing happened about 50K miles ago right after the trans was inspected and new seals installed. I was told a roll pin holding a shift fork broke or fell out. Will the linkage inside come out without removing the trans? Can a competent backyard mechanic (me) handle this repair? Where can I get a diagram or blow-up of the trans or at least the internal linkage?

Thanx- Win