Actually, the only gear I can't get it to slip in is high. And it doesn't slip on the shift. It slips when it hits about 3500 R's before the shifts. It doesn't even have to be accelerating at WOT, I can run up to 3500 mildly then it just slips away. It won't pull more than 3500 or so before the engine rev's and tach just buries. It's very strange. Intuition says it has to be the clutch but as soon as I shift it, the clutch grabs firmly and it chirps the tires. There is zero slip under a hard shift. It seems to be related to R's more than load.