I have a 2000 Chevy 3500 box truck with 2 gas tanks. The gas guage only goes to 1/2 with both tanks full and it won't pump gas from the second tank. How do I fix this.

2 of them........First Fuel Filter

One fuel filter is in the fuel pump of the Express Chevy 3500, which is used to push fuel or gasoline through the fuel line. The fuel pump is inside the gas tank. This fuel filter is a mesh or screen that prevents large foreign particles for entering the fuel pump. Access to the fuel filter is obtained by removing the fuel tank and then the fuel pump from the fuel tank.

Second Fuel Filter Location

The second fuel filter is within the fuel line itself. After the fuel pumps extracts fuel from the gasoline tank and into the fuel line, fuel flows through the line and through another filter on the driver's side of the Express Chevy 3500 under the front wheel suspension. This fuel filter cleans the small particles that escaped from the fuel tank.

Fuel Filter Types

The year of your Chevy Express 3500 determines what type of fuel filter is installed on the van. The fuel tank filter is always mesh or screen, but the fuel line filter can be of three different types. Two types are snap-on filters, while one type has clip-on ends.

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David Johnson is wrong about that. The Chevy HD dual tank has two sending units, one in each tank , one fuel pump, a fuel pump relay switch and a equalizing pump. If the truck stalls out at 1/2 tank, it is the equalizing pump. That pump, pumps fuel from the rear tank to the front. If the pump is out, the front tank empties, the truck shuts down, the guage reads half tank because the back tank is still full, but the equalizing pump won't pump the rear fuel tank load to the front. Hence the problem you listed above, not a sending unit.

to test if its the float in the gas tank, use a rubber hamer and hits 2-3 times than check guage. If the level is still wrong its the guage.

Your sending unit inside of the fuel tank is probably faulty. Unfortunately you have to drop the tank to change it.

Normally it's just a matter of removing filler tubes from side, disconnect fuel lines & electrical connections at fuel pump/sender, undo the 2 straps, & lower it down.

the gas guage on your tank is worn out that's why when he hits the higher surface he go back to empty replace it.

sokol520--Sounds like fuel pump/fuel guage sending unit. They are integrated and located inside the fuel tank, most likely.

The gas guage has a sending unit in the tank attached to the pump, there is a small circuit board on it that has smal"fingers" that send the signal to the guage.These get worn off and thus sends a false reading to the gas guage in the dash. The gas tank must be removed and a new unit put in to solve the problem. I had to do this repair to mine. As for the gas issue, just try pulling the nozzle back out of the filler neck when putting gas in, sometimes the overflow tube gets plugged up and won't allow the air to escape as the gas goes in the tank, making the gas pump think the car is full, pulling the nozzle will allow the air to escape. Hope this helps.

Most probably if you take out your gas pump/sending unit assembly out of your fuel tank you will find a broken fuel hose on the assembly. The actual pump rests in the bottom of the tank with hoses running to the top of the pump / sending unit assembly. It is probably broken around the 1/2 tank mark. When fuel level is higher than the break in the hose, everything runs fine, but once fuel level reaches under the break, the pump starts pushing fuel out of the break back into the tank and the engine does not recieve enough fuel pressure to run.