The body mounts are collapsing, as usual with factory vulcanized rubber mounts at this age. But it's especially bad with a body lift because it leaves the lift pucks loose on the bolts, which can result in the body shifting even during normal driving & braking; but also in the body ripping loose in a collision or rollover. It should NOT be possible to spin the lower mounts - certainly not by hand.
Black Energy polyurethane body mounts (~$130) don't collapse or age (except by fire), so they're far superior.
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R&R body mounts (labor only; includes center body on frame) $240