I have a 1980 TH400.I dont know how many miles it has on it.I got it and it was in good condition.I've had it in my 64 malibu and no problems and then when I switched cams and went to an edelbrock rpm cam something strange happened. I noticed that it started slipping all of a sudden.The fluid level was right on.One thing though,I have never adjusted the modulator.Also when I removed the tranny to inspect further I noticed that the vacuum line was really loose so as there was a vacuum leak I suspect.So what would you do? My initial reaction was that the tranny was going south so I bucked up and bought TCI's pro master rebuild kit and a Hughes 3500 pro race converter.Should I spend the 300 bucks to have it rebiult or throw a tranny cooler in and go?Sorry for the long post but I need the advice.Thanks JIM