Did you remove the Differential from the Sub frame when you dropped everything, and if you did, are the 4 19mm nuts tight?
Are the upper nuts (17mm) on the shocks tight? or the lower ones?
I was thinking of the Sway bar links also.
The Sway bar couldn`t be hitting the Diff mount as it goes on only one way, found that one out when I had it on reversed.

but could the 4 13mm bolts that secure the Diff mount to the body be loose?
What about the 13mm bolt in the Hub`s?
Charlie