700R4 Shifting Problem

Hi, I am having problem with my 1990 Chevrolet truck 350 transmission 700R4. When am going about 55 mph and floor it until about 65 mph, after I come to a stop and start to accelerate again it do not want to shift out of first gear. And when I shift for neutral to drive there is a hard jerk. There is a little slippage from second to third. If I wait a while sometime it work, but better in the morning. Any information would be greatly appreciated. Thanks :disappoin

How many miles and have you checked the fluid level? Mine made it about 260,00 before it was rebuild time but I really babied it. You can try some additives, all they really do is thicken the fluid to help with line pressures. Lucas brand is good. You can test the torque convertor by going around 55 and lightly tapping the brakes. You should be able to feel it locking and unlocking.