84 Caprice Odd Transmission Problems

Okay heres the story. I got this beautiful 84 Caprice, and paid only $5.00 for it because the guy thought that he ruined the engine. Turns out all it needed was a new carb. Before I got the car though, it had been sitting for 4 years straight, and then another 2 after I got it. Its on the road now, and running really great, except for one thing. The tranny is going through half a quart of transmission fluid a day. It also shifts very oddly... Before shifting into the next gear, the transmission completely lets go for a second, and then goes into the next gear. Then when shifted into overdrive, it slips constantly. I've checked the radiator for signes of tranny fluid, I've checked for puddles under my car, leaking seals, and found nothing. I tried to check for a vaccum modular, and it doesn't even have one. It has an electric component in its place. Any help anyone? Oh, if it helps any, its a 305 5.0L 4 Barrel Quadra Jet, and has a Turbo Hydra Matic 350 transmission.