You have to remove both pinions to do it. The shaft just pushes to the other side but remains in the final drive. The splined shaft is captured between the two pinion shafts and drives the inboard side of the clutches. If it is like my 500C, check the bushings in the end of the pinions as well as the nipple thon the splined shaft that goes into them for wear. Every time the clutch is released the nipple turns inside the bushing in the end of the pinion shaft.