Quick answer
In-bed diesel transfer tanks are widely used and generally legal when they're built for the purpose, properly mounted, vented and labeled. Gasoline in a bed tank is much more restricted. Rules for tank size, commercial use and hazmat vary, so check your state and federal (DOT) requirements before you buy.
This article is general information, not legal advice.
Transfer tank vs auxiliary tank
- Transfer tanks sit in the bed with a 12-volt pump and nozzle. You pump fuel out to refuel equipment, generators or other vehicles on site.
- Auxiliary tanks connect to your truck's own fuel system to add driving range.
- Combo tanks do both on some setups.
What makes a setup legal and safe
- A tank built for the purpose, not a homemade or repurposed container.
- Secure mounting: bolted to the bed or frame so it can't shift in a crash.
- Proper venting and labeling for the fuel type.
- Diesel, not gasoline, for most in-bed tanks. Gasoline vapor is far more flammable.
Commercial users and anyone carrying large quantities may fall under additional DOT rules. Ask your state DOT or a fleet compliance advisor if you run a business truck.
Watch your payload
Diesel weighs about 7 pounds per gallon. A 100-gallon tank adds roughly 700 pounds of fuel plus the tank itself. Check your truck's payload sticker, and consider helper springs to keep the truck level.
Fitting a tank with a toolbox
L-shaped tanks wrap around a crossover toolbox or sit beside side boxes, so you get fuel and tool storage in the same bed. Compact rectangular tanks fit behind a chest box. Measure carefully before ordering both.
Replacement tanks for more range
For diesel pickups, larger-capacity replacement tanks from Titan Fuel Tanks mount in the factory location and keep your bed free.
Shop transfer and auxiliary fuel tanks from Titan, Weather Guard® and TrailFX.
Frequently asked questions
Can I put gasoline in a transfer tank?
Most in-bed transfer tanks are made for diesel only. Gasoline storage is much more restricted. Only use a tank labeled and approved for gasoline, and check local rules.
Do I need a special license to carry a transfer tank?
Private owners usually don't. Commercial operations and larger quantities can trigger DOT requirements. Check with your state DOT if you use the truck for business.
Does a transfer tank come with a pump?
Some tanks are sold as kits with a pump and nozzle; others sell the pump separately. Check the product details.