You may want to replace the felts. If those have gotten hardened and arent pushing against the window they can act more like a funnel than a seal. Quick way to tell, on a morning when the truck is covered in dew, roll the window down. If it does not wipe off smoothly all the way down, the felt is gone. I've noticed this with my 2000 lately on the driver side and know it's about time to slap some new felts on the doors.