exactly what i was thinking. i went thru this as well. :shake:did you lose one of the leaf spring pads? They're low friction disks that separate the tips of the springs. Without them, the edges of the spring bites into the leaf above it and often results in creaking/squeaking sounds.
maybe a shock since it only happens on first cycle. take the bottom shock bolt out and drive around the block
EDIT i want more info on said rock crusher lift