One of the hard parts is to remove the nut that holds the part on that the drive shaft bolts into. The best way to remove the nut is to get a LARGE pipe wrench and put it on the unit that the shaft is bolted too. You will do this once the drive shaft is unbolted and removed. Then using at least 1/2 inch drive tools, even better to use either 3/4 or 1 inch drive tools.
The nut will be TIGHT and it is the lefty loosey righty tighty rule, (standard threads).
The collar SOMETIMES will slip out with a little bit of love taps on the backside of the collar. Sometimes it take some pretty good hits as it is a pressed fit onto the pinion shaft of the ring and pinion.
Once it is removed, either tap out or pry out the seal.
Reinstall is in the reverse.
One note of caution. There is an item called a crush sleeve. It will be in behind the collar, in most cases it will stay in without falling out. This crush sleeve is crushed down as you tighten the nut to hold on the collar. It is designed that way to maintain pressure on all the inter-connected parts. At my shop, I will not do this job without installing a new crush sleeve. But in your case, you probably do not have the tools to crush it down at your home. So,,, use the original and get it nice and tight. You want to use the pipe wrench to hold the collar so as not to put the pressure against the ring or pinion gears...
Good luck...
