I just fixed this problem on my truck yesterday, except my truck had the origianl automatic hubs. I figured it was the hubs making the sound, so I took them off and put on some Warn manuals. When I took the driver side hub off, I found that the axle bearing retainer nut was not tight at all. I mean it was just sitting on the bearing. If the nut up under the bearing had ever loosened up...Yikes! To tighten the nut you'll need a special socket with four little teeth on it. I got one at Autozone for $15. My Chilton's book said the nut was supposed to be torqued to 160-205 ft./lbs. After I torqued it down and put on the new hubs, the ticking disappered, hopefully for good.