My '01 super duty sounds like a bad ball joint. I checked the ball joints and they look good. However I found on the drivers side there is what looks like a dust seal that is hanging around the axle. It's hanging both near the axle tube and the hub side. When I jack it up and try to shake the wheel everything feels solid. Any ideas what this is? Should it be replaced ASAP?

 

It sounds like the outer dust seal on the axle tube. But a pic would help. It should be replaced to keep crud out of the axle tube but it's not critical and wouldn't sound like a bad balljoint. With the truck jacked up take the wheel off and get a good pry bar in there to check the ball joints for play.

If it's more of a rattle you're hearing in the front check your sway bar links and bushing.

 

That is pretty normal. My dust seals have been hanging loose for years.

 

Better check the spindle bearings also. Check for excessive play in the shaft by grabbing the u-joint ears and seeing how much the shaft will "wallow" inside the knuckle. On the 01 I just traded off the pass side spindle bearing was bad, caused that seal to fail, then let the shaft droop down until the caps of the u-joints would touch the ball joints, occassionally that hub would grab at hoghway speeds, causing the shaft to turn and some pretty scary sounding noise.

 

Unless your goin muddin up past the axles dont worry about replacing the dust/crud seal until you have to remove the shafts for hub replacement. Just cut them off and go. Common prob. They redesigned them on the 11s I believe. Mine has 60K on it seals intact. The redesign I believe is backwards compatible, in other words should fit the 01

 

Wrong post.