I have 1980 Trans Am w/'73 400 and I believe same year transmission, a TH350. The car had sat for a few years while I was stationed overseas. When I did drive the car, which was daily before it sat, I typically drove it like a manual... start off in 1st, then kinda go through the gears. Now, the car won't stay in 1st gear. I have double-checked the linkage, and it is indeed going into 1st gear, but it will shift into 2nd on it's own, nor will it downshift into 1st from 2nd when I pull the selector all the way down. It is kind of a damper on "fun" driving, and was wondering if anybody has any ideas... like maybe a simple flush/filter change or if I'm in for some serious overhualing. I'd hate to put a bunch of money into a tranny I plan on replacing with an overdrive unit (eventually).
Thanks in advance - Josh