vibration in 4wd when accelerating

the ride:89 cherokee, 5speed(ba) with 3in lift in front and 4 in rear. just did a diy alignment(issue started before).

the issue: when i put it in 4wd i get a vibration when accelerating. it might be there very slightly when not accelerating but it def get worse when accel.

additional notes: didnt always do this with lift, right side axle seal is leaking(maybe low fluid levels), need fixed for buffalo winter,

what should i start looking at? u joints? fluid level in diif? i know what to look for but i am going back to school in 4 days and working everyday til then and would like to elimate things and get addiontal prospective.

If it was me id start checking ur front drive shaft u joints

Pull front axle shaft, if vibe goes away, replace joint and/or get a new one.

thanks guys been a while but it was the front drive shaft front most u joint.