I have a 1988 1500 with a 350 and a 700r 5-speed. My problem is that I cant get it into gear without turning off the motor. When I turn off the motor and put it in gear it shifts in and out of gears fine. At first the fluid was low and I put more in and it worked great, now when I put more fluid in its still giving me the same problem. Anyone out there that could give me some advice on where to start? Id really appreciate it!

 

Might be your throw out bearing, cause ive had this happen before and you had to "Speed Shift" it, I would prolly replace the clutch and throwout bearings then see what happens.