Dynamax DX3 Locking Fuel Door — Armor for Your Super C
The Dynamax DX3 is a luxury Super C built on the Ford F-550 with the 6.7L Power Stroke diesel. Despite its premium price tag, Dynamax left the diesel and DEF caps completely exposed. The RV Fuel Vault is the exact-fit armored locking enclosure your DX3 is missing.
Why a Locking Gas Cap Is Not Enough
- ✖Your Dynamax DX3 has exposed, unlocked diesel and DEF caps — no factory fuel door
- ✖The F-550 Power Stroke carries 50-80 gallons of diesel — easy pickings for thieves
- ✖DEF contamination can destroy your SCR system — $5,000-$10,000+ to repair on a luxury Super C
- ✖Generic locking caps do nothing for your DEF tank and can be defeated in seconds
- ✖Road grit and diesel splash-back slowly damage the finish around your exposed filler necks
Why a Locking Fuel Door Beats a Locking Gas Cap
- Factory-finished look — eliminates exposed caps on your DX3
- Precision-engineered for the Ford F-550 filler neck configuration used in your DX3
- Tamper-resistant keyed lock secures both diesel fuel and DEF fluid
- High Impact Reinforced Material — complements your DX3's premium build quality
- Bolt-on in 8-15 minutes — no drilling, no cutting, no modifications
- Corrosion-proof — rated for full-time use in any climate
Before & After: Your RV's Exposed Fuel Cap vs. a Locking Fuel Door
Why You Need a Locking Fuel Door
Lead with finish. End with security.
Factory-Finished Look
Eliminates the exposed plastic caps on your DX3. Your luxury Super C finally looks complete.
Fuel Theft Prevention
Keyed lock stops siphoning at campgrounds, rest stops, and storage.
DEF Contamination Defense
Prevents tampering with your DEF tank — avoids $5K-$10K SCR system repairs.
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 Ford F-550 (Dynamax DX3) Motorhomes
The Dynamax DX3 is built on the Ford F-550 with the 6.7L Power Stroke diesel. Both diesel and DEF filler necks are completely exposed from the factory.
| Manufacturer | Models / Floorplans |
|---|---|
| Dynamax DX3 | All floorplans (37TS, 37RB, 34KD, etc.) on Ford F-550 |
| Dynamax Force HD | All floorplans on Ford F-550 |
| Also fits other F-550 Super C | Entegra Accolade XT, Jayco Seneca |
Frequently Asked Questions
Common questions about The RV Fuel Vault on Ford F-550 (Dynamax DX3) motorhomes
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