It's pretty straight forward, but takes some time.. Jack up back end, loosend track tension, remove rear idlers, all bogies, bolts are on side of tunnel. Depending on condition it might be best to use an impact to keep shaft from spinning. There should be a rubber cap at bottom of the drive chaincase. Remove cotter pin and nut. On other side of tunnel there should be a cap with three bolts in it.. Remove bolts and slide shaft out. It's been a few years since I've done it, but I think that's about it. Now would be a good time to grease everything and replace seals, drive bogies etc. I know a local ski doo dealer here can still get many of these parts and they are fairly inexpensive. Reassemble the opposite of how you took it apart. Make sure your track tension and allignment are good. Have fun!