The parts diagram shows internal cir-clips #9 on both sides of the bearing to keep the stack located. Depending on which one is not installed the "float" will allow either the gear or the end of the axle to rub on the inside of the case. The #10 nut will keep it assembled, but the axle moving in and out may cause the outer oil seal to leak. The only good news in taking it apart again is the learning curve is flatter on the second dive. Good luck, Dick B