Waveski,
Another "passenger side" place to possibly look for a squeak could be the fuel filler neck to tank hose connections or maybe the filler neck to cab rubber insulator ring. Just a minor movement amongst those parts could result in a squeak.
Check your tank straps for tightness, filler neck hose clamps for tightness and see if the filler neck is pressing harder on one section or another on the through cab insulator rubber ring.
Let us know what you find???
Dan
