There are 4 items in this fuel system on the feed side.
1) In-tank pump, it is in the tank.
2) Fuel reservoir/screener, inline unit next to the transfer case. It is not a filter.
3) High-pressure rail pump. It is (usually) behind a shield and almost perfectly in line with the driver's seat.
4) Fuel filter, inline, where the frame begins to run upward again at the front. It may also be behind a shield that has two studs that face upward through the frame. If you open the hood and look down at the frame right below the brake master cylinder you should be able to find your filter.
Now, if you have zero fuel pressure but hear a pump engage with a hollow buzz the high pressure pump is dead. If you have zero pressure and hear a pump engage with an electric buzz the rail pump is working but running dry.
I would unhook the rear lines at the strainer and point them at a drain pan and turn the key on.
