Does The RV Fuel Vault fit Ram 5500 chassis?

Yes. We have a version specifically engineered for the Ram 5500 filler neck geometry.

Does it cover both diesel and DEF?

Yes. Both the diesel fuel cap and the DEF cap are covered and secured.

I have a Dynamax Isata 5 — will it fit?

Yes. Use our Fitment Finder for your specific year and floorplan.

How long does installation take?

8-15 minutes with basic hand tools. No drilling, no cutting.

Limited Lifetime Warranty plus a 30-day satisfaction guarantee.

Is a locking fuel door better than a locking gas cap on a Ram 5500?

Yes. A locking fuel door shields the entire diesel and DEF filler area, while a locking cap only protects the threads and rarely fits the commercial Ram 5500 filler neck. The RV Fuel Vault adds a keyed, armored door over the whole assembly to stop siphoning, contamination, and tampering.

How much does the Ram 5500 locking fuel door cost and where can I buy it?

It starts at $139.95 for a single door, $279.95 for a set of two, and $419.95 for the 3-Pack with a DEF cover. Buy it directly at thervfuelvault.com with fast UPS shipping.

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.

Order Now — From $139.95

Patent Pending Made in USA Fast UPS Shipping Ships in 3 Business Days

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

Why a Locking Gas Cap Is Not Enough

✖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

Why a Locking Fuel Door Beats a Locking Gas Cap

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 Impact Reinforced Material — built for Super C ownership
Bolt-on in 8-15 minutes — no drilling, no cutting
Fits Dynamax Isata 5, Grand Design Lineage

Before & After: Your RV's Exposed Fuel Cap vs. a Locking Fuel Door

✖ Exposed cap — no security

✓ 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.

How It Installs — 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.

Manufacturer	Models / Floorplans
Dynamax	Isata 5
Grand Design	Lineage

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 $139.95

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

Order My RV Fuel Vault

Proudly Made in the USA · Patent Pending · In Stock — Ships in 3 Business Days