TH350 problem after sitting a few years.

[Green Hornet]

Recently purchased a 69 C10 with a TH350 tranny. Truck sat for a couple years. She shifts decent first to second but immediately shifts into third no matter what throttle pressure there is. If I shift it manualy everything is firm and fine. Detent/kick down cable is set to full/full, I have replaced the vacuum module with no change. My figuring is the governor in the tail shaft is stuck expanded or a return spring has broken on it. Does this sound right? anything I should be looking for before I pull the tail shaft? Only need to get the rest of fall out of it as a 700 will be in it's place before spring time.