Ya got me on where your shim goes, but in general, with a lift you need to have the nose of the differential carrier pointing above the horizon. Seems like the shim should be placed to accomodate that. Did you do the lift? Do you still have the instructions? Can you go the the manufacturer's website and ask?? The diagrams of stock suspensions do not show a shim, so it must have come with the lift kit.
My factory service manual specifies 90 ft/lb torque to the ubolts.
"Blessed is one who gives without remembering and receives without forgetting." Rabbi Eleazar, 1250 AD
93 YJ project. 4.0L, stick
MJ-7 re-body, Banks header, 2.5 " pipe, low resistence cat, Flowmaster. K&N filter thru a snorkel.