Postby ShipFixer » Thu Jul 24, 2014 2:29 pm
When the truck is off the jackstand and supporting its own weight, the air bag will contact both the top and bottom seats. It'll also touch each time it compresses.
Maybe you've got something stuck under the air bag that's creaking against metal (although I think there's a rubber spring seat across the whole surface). Can you lift it a bit and look under it with a mirror maybe?