The aluminum interior at the floor is not secured well, along the floor and wall contact. The aluminum has some loose areas that are not secured. I noticed one pop rivet. I could move the aluminum at the base of the wall, as there is some slop in its fit.
This is the squeak. The Aluminum edge at the floor.
From what I found is the floor may have some play, but it is the wall and the trim covering the linoleum (whatever it is called today) and the aluminum wall that create the squeaky floor.
I took a roll of 3/4" wide Black Electrical Tape and secured it against the aluminum on the wall and creased it so the other half was secured to the floor. Then reinstalled approximately less than four feet of plastic trim to cover the floor linoleum and the loose aluminum.
It no longer squeaks. It was loud. But... now if I need to tweak the trim on the floor... I know where it is at.
No Dexter Axle replacement. No floor being secured to the frame. Nothing. Sure, there must be some play around the corner on the floor... but it no longer squeaks.
Call me... No Squeak after Today.