Truck is a bueat...
If its not a alignment issue then i think the issues your having could be related to the lift, it could have the steering geometry out of kilter...crossover steering may help/solve the issue....I've got this setup going on my truck.....you'll have to change to a 2wd steering box and depending on your knuckle design change the pass side knuckle....and ad the crossover draglink...These guys were really helpful.....
http://offroaddesign.com/catalog/Dana44crossover.htm