My 02 Sportsman runs great,AWD works but in reverse it seems like the right hub is locking in causing the steering to pull hard one way,I've had it do it in the past after switching from 4 to 2wd in forward but never reverse.I changed the hub oil in both sides last week.Any ideas

 

This was happening to me also and i changed my armeture plates in the hub and it fixed the problem.

 

I'm thinking it's the armature plate in both hubs,the previous owner took good care of it but they let it set up for 2 years.I changed the demand drive fluid twice in both sides,which the old fluid didn't look bad.Not sure about yours but I can park mine for 5 minutes get on and it pulls to the right,goose it and it's fine,It also does it in the other wheel from time to time.I'm hoping it's the plates,if one side is not doing it the other is? Crazy!!

 

I would try replacing both plates as they are fairly cheap.

 

I replaced the plates and cleaned up everything,seems to be working good.Maybe the issue is solved