TRE 4x4 Air Differential Locker — Selectable Diff Air Locker with X-Ring Seal & Wave-Spring

Transform your traction with the TRE 4x4 Air Differential Locker. This heavy-duty locking differential (often called a diff locker or diff air locker) gives you 100% lock on demand, controlled by a switch in the cab. Built from forged 4320 alloy with a unique X-Ring four-lobed seal and wave-spring actuation, this selectable locker combines strength, reliability and smooth operation. Whether you’re tackling rutted lanes, muddy climbs, rock steps or snow, the TRE locker keeps both wheels turning together — then unlocks instantly for normal on-road handling. Backed by a 5-year warranty and UK support from OFM4x4.

Key features

• Selectable diff locker: 100% traction at the flick of a switch, unlocks for normal driving.
• Forged 4320 alloy case & gears: proven strength for heavy off-road use.
• X-Ring seal: improved air retention vs. standard O-rings in other pneumatic lockers.
• Wave-spring design: compact, reliable actuation without deep spring pockets.
• Pneumatic air locker system: requires on-board air for operation.
• 5-year warranty: confidence for expedition, work or play.

What’s included

• TRE 4x4 air differential locker assembly (axle-specific)
• Bulkhead fitting & nylon airline
• 12V solenoid valve
• Dash-mounted switch with wiring pigtail
• Basic fittings and install hardware

Not included: carrier bearings, shims, oil, or the on-board air compressor. Add a compressor and, for dual lockers, an air manifold.

Technical notes

Installation & setup

• Professional install recommended (set carrier preload & backlash correctly).
• Route air lines carefully; avoid heat and moving parts.
• Pressure-test lines before final assembly.
• Pair with on-board air compressors and manifolds for multi-locker setups.

You might also need

• Air Compressors — for running diff lockers and tyre inflation.
• Air Accessories — manifolds, pump-up kits, fittings.
• Other Differential Lockers — browse applications.

FAQs

1) What is a diff locker?
A differential locker (or diff air locker) forces both wheels on an axle to rotate together, providing maximum traction in low-grip conditions.

2) Do I need a compressor?
Yes. This is a pneumatic air locker — it requires an on-board air compressor to function.

3) What makes the TRE locker different?
It uses a forged 4320 alloy body, an X-Ring four-lobed seal for better air retention, and a wave-spring for smooth, reliable actuation.

4) Is it road legal?
A selectable locker behaving like an open differential when disengaged does not by itself establish road approval. Compatibility and lawful use depend on the exact vehicle, installation and destination. Follow the manufacturer's engagement instructions; do not engage on high-grip road surfaces or where doing so could impair safe steering or handling.

5) What’s the warranty?
The TRE diff locker comes with a 5-year warranty against manufacturing defects.

6) Will it fit my axle?
This listing covers the TRE Air Locker range. Check your axle type or contact us for fitment advice.

7) What’s included in the kit?
The locker, solenoid, airline, dash switch and fittings. Bearings and compressors are sold separately.

8) Is it stronger than stock?
Yes. The forged alloy carrier is significantly stronger than many OEM open diffs, designed for larger tyres and harder use.

Explore related categories: Differential Lockers • Air Compressors • Air Accessories