tool is to hold the clutch disc center the pilot hole while you tighten down the pressure plate. install the trans then the tcase unless you are feeling like superman. ensure engine is at same angle as you install the trans, being easier to slide shaft into hole. if have couple long screw divers you can use them on either side to line up bellhousing and slide it into position. as you may need to turn the output shaft to turn the input shaft to align the splines. then go about tcase install after trans is tightened up.