Have a 1989 Vulcan 750 A-5 and I recently pulled back the boot on the drive shaft showing the u-joint area! it was dry so I greased it with moly 60, as for the final drive area can you just drain it,and then refill where that little screw is on top (allen screw)? and if so what kind of lube do I use? I only have 8800 miles on this bike. Should I also remove the rear tire and re-grease the other end of the spline?