When I back up, as I let up off the clutch the truck shakes but I can still back up. It kind of fights me. The clutch is new. The shop says, it's adjusted correctly, but I don't know. Here in korea, every shop is an expert! But not on American vehicles! When I let up off the clutch, the pedal is almost to the top before the truck moves. When I step on the clutch, I have about two inches of free play before it gets hard. Wrong adjustment? Suggestions? Again, mechanical clutch, 3 speed. Thanks!