Ok I was driving along this morning and my transmission just dropped out of gear with a bit of a bang. Never would go back into gear. Reverse still worked and I made it the ~1-1.5 miles back home.

It dropped out twice in the past month or so for about a second before kicking back into gear. At that time I checked the fluid level and it seemed fine.

It has always been a bit rough in shifting (ive had it for about a year and a half.) but I always thought it was vacuum issues.

Is this likely to be the b2 piston?