8-3_offroading

well I picked this beaut up for 600 because of a "grinding" noise. the guy thought it was the transfer case turned out to be a bad rear. so I just picked up my "new" rear last weekend and pulled the old one off, and cant seem to figure out how the new leaf spring centering pins go into the new rear . the old rear has the centering pins in the bracket on the rear. any help would be appreciated.