Jamie, he's got a '99, not a TTB. The halfshafts (both driver and passenger side) in mine have grooves to put a C-clip in, but no C-clips. Those suckers are loose and once you remove the hub assembly you can pull them right out of the differential. If the hubs are not tightened or fit close to the assembly, the halfshafts can theoretically float in and out for however much room there is to do it in.
And yes, I have that clunk too, but after installing new gears, a locker, and 35's, I don't know what to blame it on