Transmission Woes

[stingray72]

Got a TH350 in my 72 that decided not to play nice on the way to work this morning. I'm sure this has been covered but I'm already late for work so I thought it'd just ask

I'm driving along on the interstate at 55-60mph and all of a sudden it was like the truck went into neutral. Hit the gas and the rpm's would raise but not more go-go. I got over to the side of the road and put the truck in park. Tried reverse and it worked fine and then went back to drive. It's not in first gear but won't shift up to 2nd or 3rd.

I drove in 1st and got pulled off at the next exit in a parking lot and am going to have it towed today. If the tranny is shot and going to have to go through a major rebuild or something I'll just find a 700R4 but I thought I'd get board thoughts before I did anything