I have a brother hl-5250dn with an extra tray for

I have a brother hl-5250dn with an extra tray for legal size paper. I have a problem printing loan documents sent via swiftview or elynx. I can only print on letter pages or legal pages but not both and the loan pkgs and mixed pages. I email them to my secretary who can print them ok on her Brother MFC 8640N copier/printer using the multipurpose tray for legal paper. I also have times when I can not print out pdf documents at all but I can send them to my secretary who has no problem prining them out. But, usually have no problem printing out pdf docs with mixed pages. Any suggestions? Thanks, David