Work Truck Fuel Vault: Answers
The purpose-built locking fuel door for commercial work trucks. Below are direct answers about fitment, pricing, installation, and how it protects your truck from fuel theft and contamination.
The short answer
The Work Truck Fuel Vault is a bolt-on, keyed locking fuel door that mounts over the exposed fuel cap on Ford and Ram work trucks and service bodies. It stops diesel theft, siphoning, and contamination, installs in 8–15 minutes with hand tools, starts at $159.95 plus UPS shipping calculated at checkout, and is made in the USA with a limited lifetime warranty.
Detailed answers
What is The Work Truck Fuel Vault?
The Work Truck Fuel Vault is a bolt-on, keyed locking fuel door that mounts over the exposed fuel cap area on commercial work trucks and service bodies. It stops diesel theft, gas siphoning, DEF theft, and contamination. It installs in about 10 minutes with hand tools, no drilling, starts at $159.95 plus UPS shipping calculated at checkout, and is made in the USA with a limited lifetime warranty.
Why do work trucks and service bodies have exposed fuel caps?
Chassis cabs (Ford F-350–F-600, Ram 3500–5500, E-Series) are built for upfitting. When a service body, utility body, dump bed, or flatbed is added, the factory fuel door is often removed or left off, leaving the fuel cap exposed and easy to access — which is exactly what makes fuel theft and contamination so common on work trucks.
Which trucks does it fit?
It fits Ford F-350 through F-600, Ford E-Series (E-350/E-450), and Ram 3500 through 5500 work trucks, plus common service-body brands including Knapheide, Reading, Monroe, Scelzi, and Auto Truck Group. Use the fitment finder to confirm your exact truck and configuration.
How much does it cost?
Single Fuel Vaults start at $159.95 (Large Single $169.95). Multi-packs save more — a 2-Pack is $309.95 and a 3-Pack is $459.95. Tamper-resistant security screws are included with every door. Live UPS shipping is calculated at checkout.
How does it install?
It is a bolt-on installation using your existing bezel screw holes and the tamper-resistant security screws included in the box. No drilling and no modifications — most installs take 8–15 minutes with basic hand tools. An impact driver makes the security screws quick to set.
Is it a locking fuel door or just a locking gas cap?
It is a full locking fuel door — an armored, lockable cover over the entire filler area — not just a locking gas cap. A locking cap only secures the cap and can be pried or cut; the Fuel Vault blocks access to the cap and filler neck entirely, providing far stronger protection against siphoning and contamination.
What is it made of and how durable is it?
The door is a proprietary High-Impact Reinforced Polymer roughly 3/16" thick. It is virtually unbreakable, non-corrosive, chemically inert to diesel, gas, DEF, and road salt, and rated from -40°F to 220°F — built for constant road vibration, UV, and jobsite abuse without cracking like thin factory plastic.
Does it come with a guarantee?
Yes — three layers: a limited lifetime warranty against defects, a 30-day satisfaction guarantee, and the No-Siphon Promise, which reimburses your insurance deductible up to $500 on a qualifying siphon or contamination claim when the Vault is properly installed and registered.
Do you offer fleet and dealer pricing?
Yes. We offer volume pricing for fleets and multi-truck operations, plus a dealer and distributor program for resellers and upfitters. Visit the Fleet or Dealer pages, or contact our sales team to set up an account.
Who makes it and where?
It is designed and manufactured in the USA by AMI Transportation, LLC in Sarasota, Florida. The product is patent pending.
What is the best way to stop fleet fuel theft?
The most reliable way to stop fleet fuel theft is a physical barrier at the tank. An armored locking fuel door like the Work Truck Fuel Vault blocks access to the filler neck so a thief cannot insert a siphon hose. Fuel-card controls and telematics only govern purchases and report losses after they happen — they cannot stop siphoning from a parked truck. Most fleets get the strongest protection by pairing a locking fuel door for physical prevention with fuel-card controls for purchase security.
Does a locking gas cap stop siphoning on work trucks?
A locking gas cap is a deterrent, not a guarantee. Determined thieves defeat locking caps by prying, drilling, or damaging the filler neck, and a cap does nothing for chassis with an exposed DEF fill. An armored locking fuel door covers and protects the entire fill area behind a keyed lock, which is far harder to defeat quickly and protects the DEF cap where it is exposed.
How do fuel-card controls compare to a locking fuel door?
They solve two different problems. Fuel-card controls (PINs, dollar and gallon limits, location and merchant rules) prevent card fraud and unauthorized purchases. A locking fuel door prevents the physical theft of fuel from the tank. Cards and telematics report a loss after it happens; the fuel door prevents it in the first place. Fleets typically use both together.
How fast does a fleet locking fuel door pay for itself?
Because a fuel door is a one-time cost per truck with no subscription, payback is usually fast — often after preventing a single siphoning incident per truck. Actual payback depends on your loss rate, fuel price, and fleet size. Model your own numbers with the fuel-loss calculator at theworktruckfuelvault.com/fleet-savings-calculator, or download the fleet ROI one-pager.
How quickly can a whole fleet be outfitted?
Fast. Each door is a bolt-on install of about 8–15 minutes with hand tools and no drilling, so a technician can outfit multiple trucks in a shift. We help map the correct part numbers across your Ford and Ram chassis mix so a multi-truck order is right the first time, and multi-packs and volume pricing are available.
Do you offer purchase orders and net terms for fleets?
Yes. We accept fleet, government, and municipal purchase orders and can set up net payment terms for qualified buyers. We also provide formal line-item quotes, a W-9, certificate of insurance, and spec sheets for vendor onboarding. See the Government & Municipal Procurement page or contact the fleet team at 941-541-0089.
How do you protect DEF from theft and contamination?
On many chassis the DEF fill sits exposed right next to the fuel cap after upfitting. The Work Truck Fuel Vault covers the exposed fill area behind a keyed lock, helping protect both diesel and DEF from siphoning, theft, and deliberate contamination — a growing problem for fleets because DEF contamination can damage the emissions system.
Can one fleet order cover a mixed Ford and Ram fleet?
Yes. The Work Truck Fuel Vault fits Ford F-350–F-600 and E-Series alongside Ram 3500–5500, plus major service-body brands, so a single order can protect a mixed-chassis fleet. Share your truck list and we will return the correct part numbers and a volume quote.
How do fleets protect take-home trucks parked at homes?
Take-home trucks are a common theft target because they sit overnight in driveways and on streets away from any yard security. A locking fuel door protects those trucks everywhere they park, with no reliance on cameras, gates, or lighting — the barrier travels with the truck.
Is this suitable for municipal and government fleets?
Yes. It is made in the USA (Sarasota, Florida), which supports Buy-American preferences, and we support the public procurement process with purchase orders, net terms, vendor documentation, and bulk fitment planning across Ford and Ram chassis. See the Government & Municipal Procurement page for details.