If you print to pdf does the pdf contain the data and show a page size of Letter?
Can you do a "Print to File" from the ArcGIS software?
If yes, can you post an example from the PS driver so I can tear it apart in Distiller to see what data is lost/missing?
Since it appears ArcGIS is browser based, does it output the same from multiple browsers? Chrome for example is terrible for print output in particular, Safari and Firefox are almost identical and are mostly OK if color quality doesn't matter.
I have a Phaser 7500dx that when I print to it from ArcGIS has a portion at the bottom of the page that does not print, and does not print on a second page.
It is the same with a PS or a PCL driver.
Any ideas?