The RV Fuel Vault bear logo
The RV Fuel Vault™
The Part the Factory Forgot

Ram 5500 Locking Fuel Door — The Part the Factory Forgot

The only locking fuel-door enclosure purpose-built for Super C diesel motorhomes on the Ram 5500 chassis.

The RV Fuel Vault — Locking Fuel-Door Enclosure — locking fuel door for motorhomes

The Problem

  • ✖Every Ram 5500 Super C ships with exposed diesel and DEF caps — no fuel door
  • ✖The Cummins diesel powertrain carries premium fuel worth hundreds per tank
  • ✖DEF contamination on a Cummins system can cost $5,000-$10,000 to repair
  • ✖Generic truck fuel doors do not fit the Ram 5500 Super C body geometry
  • ✖Neither Ram nor the RV builder offers a fuel door from the factory

The RV Fuel Vault Solution

  • Precision-engineered for the Ram 5500 filler neck configuration
  • Factory-finished look on your Cummins-powered Super C
  • Tamper-resistant keyed lock secures diesel fuel and DEF
  • High-strength fiber-filled polymer — built for Super C ownership
  • Bolt-on in 8-15 minutes — no drilling, no cutting
  • Fits Dynamax Isata 5, Grand Design Lineage

See the Difference

Exposed cap — no security
✖ Exposed cap — no security
RV Fuel Vault installed
✓ RV Fuel Vault installed

Why You Need a Locking Fuel Door

Lead with finish. End with security.

Factory-Finished Look

Eliminates the exposed plastic cap. Your rig finally looks production complete.

Fuel Theft Prevention

Keyed lock stops siphoning at campgrounds, rest stops, and storage facilities.

Contamination Defense

Prevents sugar, water, or foreign substances from being added to your fuel tank.

Vandalism Protection

Tamper-resistant design deters opportunistic damage to your fuel system.

Installs in 8–15 Minutes — No Drilling, No Cutting

8–15 Minutes

Average install time

Basic Hand Tools

No special equipment needed

100% Reversible

No drilling, no cutting, no mods

Compatible Ram 5500 Motorhomes

The Ram 5500 with 6.7L Cummins diesel is the alternative to Ford in the Super C segment.

ManufacturerModels / Floorplans
DynamaxIsata 5
Grand DesignLineage
Don't see your model? Use the Fitment Finder — we likely fit your rig.

Frequently Asked Questions

Common questions about The RV Fuel Vault on Ram 5500 motorhomes

Not Sure If It Fits Your Rig?

Our Fitment Finder checks your exact year, make, model, and floorplan in seconds.

Find My Fit

Order Today — Starting at $99.95

Single Door, Set of 2, or 3-Pack · Free Shipping · Limited Lifetime Warranty · 30-Day Guarantee

Order My RV Fuel Vault

Proudly Made in the USA · Patent Pending 64/085,223 · Est. delivery by July 4, 2026