yeah you can actually tell with the truck still on the ground if you really lean on it hard. It will rock and make a thump sound. Verified on my buddies 1500.

 

To check them jack the truck up and grab the top and bottom of the wheel and push back and forth to feel for any play. Any noticable play is too much.

 

I just grease and adjust the hub bearings on my '98 - 220K miles so far...

 

I understand greasing the hub bearings but how do you adjust them?

 

I thought these unit bearings were sealed and not greaseable

 

They were not designed to be greased after the factory but I found out by accident when I was changing the upper ball joints on both sides. When I removed the drivers side with a puller the hub assembly came apart in two as it is only pressed together. I changed the ball joint and cleaned up the ***** and seats, regreased used the axle nut to press them back together. When I did the other side that same night it came off in one piece so I changed the upper ball joint and just reinstalled the hub. Well the hub that did not come apart and get regreased was the one that dried out a few monthes later and vomited all of the ***** on the road. A tow truck and about $350.00 later I was back on the road. I now purposely leave the 4 bolts on the back of the hub and pull them apart, clean and regrease. Works for me. I will get the kits to change to a changeable bearing when my hubs finally go bad.