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PRODUCT CODE: RD121

ARB Air Locker 30 Spline, 3.73 and Down Gear Ratio - Front Toyota 8 inch Axle

The toughest, unmatched traction aid for your Toyota 4x4

Sold as a Single item

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EST. ARB Fitting Charge + $1280.00 AUD

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5 Years Warranty

Fitment Guaranteed

ARB Air Locker 30 Spline, 3.73 and Down Gear Ratio - Front Toyota 8 inch Axle

An ARB Air Locker is Born

Ever wondered how a genuine ARB Air Locker is manufactured? Wonder no more as we put you inside the machines that make the world’s best 4×4 traction aid, right here at our global headquarters in Melbourne, Australia.

FEATURES

Hotspot 1

Flange cap assembly—Fully machined nodular iron flange cap incorporates the stationary side of ARB's tough, proven and patented timed locking mechanism.

Hotspot 3

Clutch gear—ARB's patented locking system actually supports the side gear teeth, giving you more torque handling capability, exactly when you need it.

Hotspot 4

Cross shaft retaining pin—Custom made, one-piece hardened retaining pins lock into the assembly using a tapered thread junction.

Hotspot 5

Bonded seal—Steel reinforced, elastomer-bonded annular seal has been proven to handle 20,000+ cycles under the most extreme climatic temperatures on earth.

Hotspot 6

Two piece design—Machining a case from two pieces instead of three results in a much higher dimensional accuracy of the finished assembly and has allowed ARB engineers to improve the design of other elements, resulting in a reduction of moving parts, increased strength and a more responsive activation.

Hotspot 7

Pinion gear—Combining the strength of forged nickel alloy steel with redefined gear-tooth geometry, ARB has revolutionised locking differential gear design to yield structural advantages of up to 30% over commercially available high strength gears.

Hotspot 8

Spider block—A billet machined, alloy steel spider block supports the cross shafts, using the torque applied at each shaft to support the next shaft along.

Hotspot 9

Forged gears—With phenomenal forces being applied to the side and pinion gears within the differential, ARB has invested heavily in the application of forged gears, typically found in heavy duty commercial, race and agricultural transmissions.

Hotspot 10

Splined side gear—High grade surface treatments, forged nickel alloy steel and ARB's patented timed locking system make this the most ‘lockable’ gear in the industry.

Hotspot 2

Air supply—At the flick of a dash-mounted switch, compressed air is delivered to the seal housing assembly via a nylon air line.

Hotspot 11

Return spring—Instead of a complex external actuator system to engage/disengage the lock, ARB Air Lockers use up to 12 return springs to support the entire profile of the locking gear for a fast, positive and independent disengagement.

Hotspot 12

Diff case—Fully machined, one-piece nodular iron diff carrier case offers the rigidy of a one-piece factory differential with twice the standard number of pinion gears to cope with the torque.

Hotspot 13

Long cross shaft—Alloy steels and performance surface technology make for a high pressure running fit that can handle an enormous amount of punishment.

COMPETITIVE USE

Of the many ARB products seen in off road competition, it’s the one you can’t see that makes the difference. ARB Air Lockers continue to dominate the world’s toughest off road events as they are used by some of the biggest names in off road competition.

FORGED GEARS & TWO-PIECE DESIGN

All models include a 2-piece nodular steel housing for rigidity and exacting tolerances, housing four forged and hardened pinion gears to handle extreme axle loads. ARB’s patented ‘timed gear’ design and high-temperature resistant seals ensure responsive activation under the most extreme climatic conditions on earth.

Air Locker Destruction Test

In order to continually improve the product, our engineers are constantly trying to break Air Lockers. We even built a specialised test rig to allow us to place torques on the Air Locker far in excess of what’s possible in the field. In this static torque failure test, we used a high performance Dana 44, 33 spline diff with the best axle shaft we could get our hands on to put the Air Locker to the ultimate test.

ARB AIR LOCKERS

Those who enjoy heading off the beaten track in their 4×4 know that even the most familiar tracks can present you with unexpected conditions. Whether you’re up against a steep incline, uneven & rocky terrain or a slippery muddy track, being able to take advantage of traction is one of the most important elements.

In a vehicle with open differentials in 4WD mode, drive can only go to two wheels at any given time. At the flick of a switch, an ARB Air Locker can send equal drive to both wheels on an axle allowing you to take advantage of the wheels that have traction and push forward along the track.

5 Years Warranty

For total peace of mind, all ARB Air Lockers are backed by a comprehensive, five year, unlimited-kilometre warranty. Coupled with ARB’s extensive domestic and international network of stores and distributors, you can be sure we’ll be there to support you in the unlikely event of an issue.

ACCESSORIES

AIR COMPRESSORS

ARB Air Compressors provide many advantages when exploring the great outdoors. Whether for inflating tyres and camping accessories, running air tools, activating Air Lockers or even re-seating a tyre onto a wheel, there’s a model available to suit your needs.

Designed to withstand harsh Australian conditions, each ARB Air Compressor is individually leak tested, current draw tested and flow tested under heavy load at the factory before packing.

ARB DIFF COVERS

When off road, it is inevitable that you’ll encounter obstacles that could potentially inflict expensive damage to your differential. ARB’s differential cover provides increased protection over factory diff covers, giving you peace of mind to tackle more challenging terrain.

Each cover is manufactured from high tensile nodule iron to protect the ring and pinion set whilst computer optimised cross bracing increases the structural integrity of the entire axle.

ARB diff covers are powder coated either red or black, CNC machined, then clear coated for a durable, professional, long-lasting finish.

ARB DIFF BREATHER KIT

A diff breather kit stops your differentials (as well as gearbox and transfer case) from sucking in water when driving through river crossings and large water hazards, leading to serious and expensive repairs.

As your vehicle’s differentials, gearbox and transfer case heat up under normal operation, the air inside expands and increases pressure in the casings. To manage this increase in pressure, most of these components come standard with a series of one-way-valve breathers to allow the pressure build-up to escape.

However, when you enter a river crossing or large water hazard, the cold water quickly cools the expanded cases causing them to quickly retract in size; this forms a vacuum effect on the breather valves.

One-way breather valves will not let any air in, and as a result, water will often be sucked in through your surrounding oil seals allowing water ingress into your casings, axles and differentials; leading to corrosion and serious damage.

To overcome these common issues, it is recommended to install a breather kit which acts similar to a snorkel for your differentials, gearbox and transfer case. The breather kit is primarily a hub which transfers air in and out of the critical vehicle components; the kit includes a length of air tubing which is run to a high point (usually under the vehicle’s bonnet) where it is most protected from dust and water ingress when drawing air back in.

Out of the box, the 4 port ARB Diff Breather Kit can be connected to all four key components (front diff, rear diff, transfer case and gearbox) and comes with enough tubing and fixtures to connect to the most common application of two differentials. With a small amount of additional tubing and fixtures (sold separately), the one kit will also accommodate your transfer case and gearbox.

AIR LOCKER TOOLS

ADJUSTER NUT PLIERS

For correct pre-loading of an adjuster nut type differential, these Adjuster Nut Pliers have been specifically designed to easily and safely accommodate the full ARB Air Locker range of adjuster nuts and most original equipment types.

SHIM DRIVER

For installing and servicing common shim pre-loaded differentials, the Shim Driver is designed to evenly distribute the installation force around the outside edge of a differential shim as it is tapped into place, allowing thinner shims to be inserted into tighter places than would otherwise be possible.

DIFFERENTIAL SPREADER

To achieve the required carrier bearing pre-load during set up, the Differential Spreader has been designed to be quickly and easily used with most shim adjusted automotive differentials. It allows the housing to be stretched in a safe and controlled way, reducing the risk of damage.

BEARING PULLER KIT

The Bearing Puller Kit offers a unique way of removing a differential carrier bearing, which allows easy removal of the original bearings with less chance of damage.

TEST GAUGE

This product provides an easy and effective way to determine the supply pressure and/or to detect a loss of pressure in the air system of the ARB Air Locker or the air compressor.

SERVICE AND PARTS MANUAL

To view or download the service and parts manuals, visit ARB Service Centre.

ARB SERVICE CENTRE

DEMANDING MORE ADVENTURES?

Go even further with our extensive range of compatible gears.

Air Compressors

ARB Air Compressors provide many advantages when exploring the great outdoors. At ARB, we design and manufacture a range of high output 4X4 air compressors built for long-term performance.

TYRE & COMPRESSOR ACCESSORIES

From inflation kits to pressure gauges, ARB’s tyre compressor accessories make on-the-go tyre management fast and accurate.

SUSPENSION

Old Man Emu produces suspension to suit you, no matter your lifestyle.

LINX

LINX is a unique modern controller that declutters the dashboard and centralises the command of vehicle accessories.

Closer Look

The ARB Air Locker is your ultimate traction solution for conquering challenging off-road terrain. Engineered for reliability and performance, this selectable locking differential provides 100% traction on demand to your vehicle's front wheels without compromising on-road driveability.

This specific Air Locker model, featuring 30 splines and designed for 3.73 and down gear ratios, is precision-engineered for the Toyota 8 inch front axle found in a wide range of Toyota Hilux, Fortuner, FJ Cruiser, and Prado models. When activated, it ensures both wheels on the axle receive equal drive, eliminating power loss to the wheel with the least grip +ô+ç+¦ a common limitation of standard differentials.

Built in Australia from high-strength, aerospace-grade materials, the ARB Air Locker is trusted by off-road enthusiasts globally. It provides the confidence to navigate steep inclines, rocky obstacles, and slippery tracks, transforming your Toyota 4x4's capability. Disengage the Air Locker for safe, predictable handling on sealed surfaces.

Fitting Position Front Axle

Axle Independent wheel suspension

Axle Code Toyota 8"

Number of Teeth on input shaft 30

for shaft diameter [mm] 33

Gear Ratio 3.73 &DN

Specification Ring Gear

Outer Diameter [mm] 200

Bore diameter [mm] 126

Number of Holes 10

for bolt hole circle diameter of [mm] 160

Tightening Torque [Nm] 95

Backlash 0.15-0.25mm

Oil Viscosity Classification SAE API GL-5

Warranty 5 Years

Net weight [kg] 9.6

Fitting Instructions

Differential_Installation_Record_215762A.pdf

2-RD121.pdf

2102121_RD121.pdf

Additional Info

Shipping Info & Returns

Warranty Policy

Environmental Impact

Ask an Expert

If you need any assistance, come have a chat with our ARB team. Learn more about this product, compatibility or help construct your dream vehicle.

ARB 4×4 Accessories Keilor Park

34 Commercial Place, Keilor East, 3033 VIC

03 9331 7333 Store Info

50 Years of Adventure, Innovation & Community

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Thank you for being part of the ARB convoy! Here’s to many more tracks, trails, and adventures together!

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ARB Air Locker 30 Spline, 3.73 and Down Gear Ratio - Front Toyota 8 inch Axle

The toughest, unmatched traction aid for your Toyota 4x4

An ARB Air Locker is Born

FEATURES

Air Locker Destruction Test

ARB AIR LOCKERS

5 Years Warranty

ACCESSORIES

AIR LOCKER TOOLS

ADJUSTER NUT PLIERS

SHIM DRIVER

DIFFERENTIAL SPREADER

BEARING PULLER KIT

TEST GAUGE

SERVICE AND PARTS MANUAL

DEMANDING MORE ADVENTURES?

Air Compressors

TYRE & COMPRESSOR ACCESSORIES

SUSPENSION

LINX

Closer Look

Fitting Instructions

Additional Info

Compatible Gear

Ask an Expert

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