When is the last time you changed your fuel filter? If you sucked some crap up from the empty front tank, you may have plugged it up gunk and need to change out the filter before you destroy your lift pump. I don't usually hear anything when I switch tanks either, but then again the truck is usually running when I do that. As far as the fuel gauges, I have the same problem, but that's because both the senders in the tank are screwed, I can only tell when my rear tank is almost empty as the needle starts to bob around a little.