Accidentally putting gasoline in a diesel fuel tank
I know people have accidentally pump gasoline into diesel fuel tank. The tough part is proper repair for this would be to have the truck towed to a shop or home and have the entire diesel fuel tank dumped of the gasoline and diesel fuel mixture and fresh diesel fuel put back in the fuel tank before starting the engine. Some people just are busy and not paying attention and end up grabbing the gasoline hose instead of the diesel. The quantity of diesel fuel remaining in the fuel tank and the amount of gasoline pump on top of the existing diesel fuel is what will make the decision on towing or not. If there is a majority of diesel fuel compared to gasoline you might just get away with adding 2 cycle oil to the fuel say 64:1 to 128:1 ratio to bring the lubricity back up in the fuel. The other thing is gasoline is very high cetane rating. Back years ago and some still do mix kerosene or gasoline to the diesel fuel to prevent diesel fuel gelling. So if you do happen to pump gasoline fuel in your diesel truck small amount you can get away with adding 2 cycle oil. Do not use ATF which is way too high in ash content and will create other issues on top of the gasoline diesel mixture you've got now in the fuel tank.
For truck owners that have a AirDog or FASS fuel system, you could use a jumper wire in the relay and output line. Basically, disconnect your fuel line and pump the gasoline mixed diesel fuel out of the fuel tank using a jumper in the relay socket this way the pump does the work for you and pumps the fuel tank empty if your gasoline to diesel mixture was too high.
If you still have the factory fuel system you could disconnect that at the injection pump or lift pump. Then using a shop vacuum reverse the hose so it hooked up to blow air. This should produce enough pressure at the filler neck to push the fuel out of the tank and through the fuel line to a buckets or fuel container.
As for siphoning fuel from the filler neck is impossible on most Dodge Ram truck being there is a rollover ball in the tank neck. This prevents you from getting into the tank bottom and getting the fuel out from the filler neck.
Be aware that most shops charge a hefty fee for disposing of gasoline mixed diesel fuel. In the same token running the gasoline mixed diesel fuel in the truck will most like cost even more in damages to injection pump and fuel injectors replacements.