The what pin? 
The diff didn't bind when I drove in a circle at the Co-op parking lot. Looked weird doing it I am sure.
The axle that we pulled off didn't feel like it had any weirdness. Didn't take off the boots in case it was something else.
Sounds good. Could you pm me a price for it? Thanks. Why do you have a spare axle?
You first 
on most lsd's depending on what kind, visco /mechanical/clutch type there while be a thrust block that prevents the axles from moving inwards when corning( car goes left, left axles tries to push through the diff and right axles tries to pull out) that's what the thrust block/pinion block and circ-clips are for on the axles to keep minimal movement on side thrust forces and allowing a suitable rest position, (1) but what I have seen is if the clips are worn or the cv-shaft splines are worn then the axle can force it self out when load is applied to the lsd and power it sent to the side with the weakened clips ---- OR----- (2) if there is only One Pinion block not two, like more Lsd are, then back to what I first said earlier, the cotter pin that holds the block in position can break , allowing it to turn which will not give the cv stub the space required to fit correctly in the differential,
I had this exact problem with my r160 diff when I had it, take it or leave it just take a peek in the drain hole or fill hole and see if and thing looks out of place in the diff, I could be completely over thinking but it worth the 5 mins to check.
