I've read on here about te Seth wobble you ge from our poorly made steering components and how they loosen up over time. But idk if this is the case on mine. After 65mph, I get a very loud rattle that's coming from the front, but then as speed increases, it moves more to under me. I have a 98 1500 4x4, an the 4wd lever actually starts horrifically shaking and I can feel the transfer case going ballistic down there at about 80. 4wd works well to my knowledge. Could this be a driveshaft imbalance? Tranny was rebuilt by me and a friend and it's fine. I personally saw it all go back together fine. Idk if it could be such a bad wobble in the front that it is wobbling the axel, to the front driveshaft then tcase then also tranny. Any help would be much appreciated. Thanks guys

 

*death wobble

 

Here is a visual depiction of death wobble:

 

Death wobble is more you hit a bump and then the truck goes ballistic and you lose all or almost steering capacity.

Sounds like your t case is bad. Or something like that. Take your front drive shaft and see if it goes away.

 

Will do, thanks