Sometime over the summer the auto-locking hubs on my 94 Limited decided to quit working. They would sometimes engage (when they didn't, they would instead make a horrible grinding and/or clunking noise), and when they did engage, they would then not disengage - or one side only would disengage. I would have to jack the front end up, hold the wheel, and jiggle the drive shaft forward and backward by hand to get them to disengage. Now I know you rabid manual-hub-loving freaks here think it's great fun to get out and schlup around in the mud and snow every time you want to turn your 4wd on and off, but call me crazy - I'd rather just sit in the comfy dry warmth of my truck and push a button. So I read up a bit here, and decided to have a look at them. The hardest part was sending my wife to NAPA to buy the "cheapest bottle of automatic transmission fluid they have." The guy there, bless his heart, refused to sell her the cheapo NAPA brand, saying, "you don't really want to put that in your car." When she told him that it was actually for "the wheels on my husband's truck"...well, let's just say he shook his head, figured she was a dumb blonde (she is not - well, she is blonde, but not dumb) who had no idea what she was talking about, and sold her the cheapo fluid. When I pulled the hubs off, they were absolutely PACKED with grease, as was the mechanism on the spindle. I bought a big can of brake cleaner and cleaned all the grease off the spindle mechanism. I filled the hubs with brake cleaner a couple times, worked the spring mechanism up and down, and emptied it, each time watching gobs of grease fall out. Then I filled them with hot ATF, let them sit a half hour, dumped them out, and did it again. The second time I let them sit overnight full of ATF, then dumped them out and let them drain for an hour or so. Lastly I put a thin film of new grease on the spindle mechanism, fitted the hubs back on...and hey presto, they work better than they ever have. So if you are having problems with your automatic locking hubs, don't be swayed by the fanatical "you must convert to manual hubs" cult that hangs out here - a little bit of cleaning and chances are you'll be as good as new!