The other day on my way home I was going about 45-50, stepped on the gas to go up a hill, and the RPM's went up, but the car didn't move any more. I let off the gas, and it went back into 4th. If I put it in 3rd, it works fine. But in 4th at anywhere between 40-70 mph, when I give it more gas, it slips and won't grab into 3rd. The same thing happened about 2 months ago and after a few days of this, I completely lost 3rd and 4th. Last time, the shop put in a better 3-4 clutch pack, a new, wider band, and a super hold 4th servo. When I got it back, and ever since he first built it, it shifts alot harder into 1st at part throttle than it did at WOT. I'm pretty sure the guy doesn't have a clue about building performance trannys. Can someone tell me EXACTLY what to tell this guy to do to make this thing work the way its supposed to? This will be the THIRD TIME it's been to his shop in less than a year. My mom's getting pissed that I have to keep borrowing her car for weeks at a time.