Within the last couple months there has been a decent amount of shuddering (coming from the rear end as far as i can tell) that occurs while I'm slowing down from any speed over 45 or so and it is more pronounced the higher the speed. Does it sound like rear diff or u-joint? I looked around on the forums and could only find similar issues while the truck is accelerating but I don't have that problem. 2001 F150 4x4 w/190k

 

try popping it in neutral before you slow down and see what happens

 

Tried coasting in neutral, shuddering was still present