Gravity Feed Fuel Tanks
What a Gravity Feed Fuel Tank Is
A gravity feed fuel tank is an auxiliary diesel tank that sits in your truck bed and refills your factory fuel tank using nothing but gravity. There is no pump, no wiring, no switch to remember, and no transfer to manage. Fuel flows down from the bed tank into your factory tank through the factory fill neck, and it keeps flowing until the auxiliary tank is empty. Your factory gauge simply stays on full while the bed tank does the work.
Gravity feed is the simplest and most reliable way to extend the driving range of a diesel pickup. With a 30 to 80 gallon auxiliary tank in the bed, a diesel truck can skip fuel stops for days, run remote job sites without hauling fuel cans, and buy fuel where it is cheap instead of where the tank happens to hit empty.
How the Fuel Shotz Gravity Feed System Works
Aluminum Tank Industries builds its diesel auxiliary tanks around the Fuel Shotz installation kit, a gravity feed system that connects the bed tank to your factory tank through the factory fill neck. Here is the whole system:
- The auxiliary tank mounts in the truck bed, up high, so gravity has somewhere to work.
- A fill neck adapter connects the auxiliary tank's outlet to your factory fill neck. No cutting, no drilling into the factory tank.
- A shutoff valve lets you stop the flow when the system is not in use.
- Rollover protection is built into both the tank vent and the fill neck adapter for safety.
Because the factory tank is refilled through its own fill neck, the system does not interfere with your truck's fuel system and does not void the truck's warranty. Installation typically takes under an hour with basic hand tools, and there are no wires or switches to install.
Which Install Kit Fits Your Truck
The Fuel Shotz kit comes in three versions, matched to the fill neck on your truck. Find your truck below:
| Your Truck | Install Kit |
|---|---|
| Ford, Chevy and GMC (2011 to current), Dodge (1999 to 2012) | AIK15FD |
| GMC and Chevy (1990 to 2010) | AIK20C |
| Dodge (2013 to current) | AIK175D |
The kit works with any properly vented diesel auxiliary tank that has a 3/8" NPT drain, which includes every ATI diesel auxiliary tank we carry.
Why Gravity Feed Is Diesel Only
Gravity feed works for diesel because regulations allow diesel to be drawn from the bottom of the tank, which is where gravity needs the outlet to be. Gasoline is different. Federal rules require gasoline to be drawn from the top of the tank, so a gasoline auxiliary tank cannot gravity feed no matter how it is plumbed.
A gasoline auxiliary tank instead uses a small inline fuel pump mounted to the truck frame, with a toggle switch in the cab. You flip the switch when your main tank gets down to about a quarter, and switch it off once the main tank fills. The pump is not included with the tank, and gasoline tanks come with the fuel pickup and return fittings already built in.
Choosing a Gravity Feed Tank
ATI diesel auxiliary tanks run from 30 to 80 gallons in rectangle, wedge, and L-shape bodies, in bright diamond plate aluminum or black powder coat, including tank and toolbox combos that add lockable storage in the same footprint. A few pointers:
- Bed space: low profile rectangles fit under most toolboxes and tonneau covers, wedges hug the bulkhead, and L-shapes wrap over the wheel wells.
- Capacity: more capacity means fewer stops, but check your payload. Diesel weighs about 7 pounds per gallon, so an 80 gallon tank adds roughly 560 pounds when full, plus the tank.
- Fuel level readout: a fuel sender and dash gauge can be added to rectangle tanks. Senders are not accurate on wedge or L-shape bodies, because the wide bottom holds far more fuel than the narrow top and a float cannot read that shape correctly.
Common Questions
Does a gravity feed tank void my truck's warranty?
No. The Fuel Shotz system connects through the factory fill neck and does not modify the truck's fuel system, so it does not void the truck's warranty.
Do I need to switch anything on or off?
No. Gravity feed runs on its own. The system includes a shutoff valve for when you want to stop the flow, but in normal use the factory tank simply stays full until the auxiliary tank runs empty.
Can I use a gravity feed tank for gasoline?
No. Gasoline must be drawn from the top of the tank under federal rules, so gasoline auxiliary tanks use an inline pump instead. See our gasoline auxiliary tanks for the pump based setup.
How long does installation take?
Typically under an hour with basic hand tools. There is no wiring and no drilling into the factory tank.
Are these tanks road legal?
ATI diesel auxiliary tanks meet DOT requirements for diesel auxiliary fuel tanks, with .125" HD aluminum construction, internal baffles, and rollover and vent protection. It is the user's responsibility to comply with local, state, and federal requirements pertaining to safe transportation, loading, and discharging of tank contents.
Ready to Skip the Fuel Stops?
Browse our full lineup of diesel auxiliary fuel tanks from 30 to 80 gallons, or see all auxiliary fuel tanks including gasoline models. Not sure which tank or kit fits your setup? Call us at (863) 261-8388 and we will walk you through it.