u say u can put it in gear and drive it but can't shift,,then the clutch and PP is ok your problem is in the shifter ,,slave,,cable,,fluid. have u tried to shift with the rpm of the engine,,, over my 397 AMX's that i have owned i have bought over 50 of them with clutch problems,, put it in 1 gear start the motor go to about 23to2500 rpm as u ease off the gas pull it out of 1 and then (between gears) give it a little gas as u push it into 2 gear,,,takes practice ,, i use to do it a lot so go for it if that works your clutch and PP are good. jim