I was an IDIOT for buying a Thor Palazzo!!!

From an amateur engineering look I'd say they have the rack and drive gear assy in the wrong location (on the side). The slide rack should be on the bottom of the slide out so that the s/o weight works for you. As it is now, any misalignment or wiggle will eventually strip the gears.
I believe most other makes use this approach, my current Entegra does as well as my last Monaco.
Of course it's doubtful those small motors could handle that much additional slide weight.