JYINCPED 2" Threaded Transfer Tank Vented Fuel Cap — Lockable Diesel Cap with Pressure-Relief Vent

JYINCPED's 2-inch threaded transfer tank vented fuel cap is a lockable replacement cap designed to vent pressure both ways while sealing tightly to prevent leaks and theft on diesel transfer tanks.

Replace a worn or missing transfer-tank cap with this heavy-duty, threaded 2" fuel tank cap engineered for transfer tanks, auxiliary tanks and mobile fuel systems. It fits standard 2" NPT threaded bungs used across many truck and trailer installations and is built to resist corrosion and weathering. The cap combines a pressure-relief vent, a secure gasket seal and a shackle padlock-ready tab so your diesel supply stays protected and functional in the field.

How does this cap keep fuel from leaking while driving?

The cap uses a spring-loaded closure and an internal gasket that compresses when tightened, forming a durable seal against liquids and vapors. The threaded base provides a secure mechanical fit that resists vibration and movement common during transport.

• Spring-loaded seal for constant pressure against the gasket
• Internal gasket material blocks liquid and excess vapor escape
• Heavy-duty 2" threaded cast-iron base locks into the bung securely
• Designed to tolerate road vibration and weather exposure

What happens to tank pressure when filling or dispensing fuel?

This cap vents both directions: it allows built-up pressure to escape when loosening and admits air when fuel is removed, preventing overpressure and vacuum formation. You can relieve tank pressure carefully by turning to the vent notch, improving safety during service and fuel transfer.

• One-way venting when loosening prevents sudden vapor release
• Air intake prevents tank collapse during fuel withdrawal
• Controlled venting reduces dangerous vapor accumulation
• Clear vent notch indicates the safe opening position

Will this cap fit my truck or transfer tank?

The cap is made for standard 2" NPT threaded bungs and is a common replacement for Fill-Rite/Dee Zee-style transfer tank installations. It is suitable for many pickup and service truck tanks as well as farm and commercial transfer tanks.

• Standard 2" threaded neck fits widely used transfer tank bungs
• Compatible with many diesel, gas, and auxiliary fuel tanks
• Works on trucks such as Ford, Chevy, GMC, Toyota, Nissan, Ram and more with 2" female threads
• Fits mobile fuel setups, weather guard tanks, and service bodies

How does the lock feature protect my fuel supply?

The cap includes an integrated tab with a hole sized for 1/4"–5/16" shackle padlocks so you can deter theft and tampering. When locked, the tabs prevent cap removal and discourage siphoning or vandalism at job sites or unattended storage.

• Padlock-ready tab accepts 1/4"–5/16" shackle (padlock not included)
• Locking tab secures cap to base to prevent unauthorized removal
• Adds a physical theft deterrent to remote fuel tanks
• Simple installation and locking for quick security upgrades

Who is this for: This JYINCPED vented transfer tank cap is aimed at contractors, farmers, fleet managers and pickup owners who use transfer, auxiliary or mobile fuel tanks and need a durable, vented, lockable replacement for a 2" threaded fuel bung. It's a practical choice when you want reliable sealing, controlled venting and added theft protection for diesel, gasoline or distillate tanks used in field, commercial or on-the-road environments.