Ok so Ill start by saying I have the non-vacuum style automatic locking hubs. They are the centrifugal style warn automatic locking hubs.

When I first got the sporty they would lock/unlock properly it seemed. after a while i noticed I would have to back up to get them to fully unlock and i never noticed that I had to do that before. I wasn't sure if this was how they were supposed to work. so I pulled the hub off and cleaned and re greased it. now just 2 days ago I think the hub is trying to lock itself in. but only seems to do this after I have reversed. So if i back out of a parking spot then start driving forward it seems normal. until about 40km/h or so then i can hear it whining like its trying to lock in. so if i slow back down at about 10km/h BANG it will pop out and stay out. until the next time I reverse. I pulled the hub off the wheel again and looked and I cant see any major evident problems. I put a little more grease on everything and took it for a drive and it made th whining noise but there was no bang this time. then it just went away. could it have been just not enough grease? I liked these hubs until now. for the past 3 months I have been at a job site with a lot of sand. so the hubs have been getting a workout in 4x4 all day until i leave the site.