What year is your Navigator, and does the suspension warning ever show up on the dash? Also, does the bounce happen all the time or only after it's been sitting overnight? That would tell you a lot about whether it's a leak or the dampers themselves.

Is the scuff through the paint to bare plastic, or just marks sitting on the surface? And has the bumper cracked or deformed at all? That decides whether it's a quick polish, a spot repair or a full respray.

Is the scuff through the paint to bare plastic, or just marks sitting on the surface? And has the bumper cracked or deformed at all? That decides whether it's a quick polish, a spot repair or a full respray.

Air suspension faults usually leave codes for height sensors, compressor or valve block, so a proper diagnostic printout is the starting point. Ask for it in writing, along with a physical check of the bags, links and rear control arm bushes. Clunk plus float can be two separate problems.

Had a cheap plastic pallet crack on me after a rocky trail near Hatta, wasn't even that overloaded. Went back to steel frame after that, more weight but I stopped worrying about it snapping under the toolbox.