Typical pinbox/frame mounting issue. The underlying frame structure is compromised and must be repaired by re-welding and strengthening with more steel. The bottom panel must come off for access. I saw a recent post here, or at rv.net or irv2.com; do a search on pin frame failure to read up on the fix. Lippert supposedly has someone traveling the country doing the repairs, but don't expect any warranty help unless they're being real generous.
--2005 F350 Superduty Crewcab, 6.0, 4wd, short bed, 3.73 gears;
--2016 Montana 3711FL, 40'
--2014 Wildcat 327CK, 38' SOLD