Can you define "getting weak"? Is the clutch slipping, or gears grinding, does it need to be adjusted to 3/4" free lay in the pedal? Does the hydrualic pickup screen need to be cleaned? If it really needs replacement, they are all pretty much the same. Block up the frontend, put a floorjack or suitable, moveable lift on the rear and keep taking stuff loose until it splits apart at the bellhousing and roll the rear half back.