Longfield LC79 30-Spline Gun-Drilled Birfield & Axle Kit – Toyota Land Cruiser 79 Series 1999-on

The Longfield LC79 30-Spline Gun-Drilled Birfield & Axle Super Set is a complete heavy-duty front axle upgrade for the Toyota Land Cruiser 79 Series from 1999-on.

Designed for demanding off-road, overland and high-load applications, the kit combines Longfield gun-drilled 30-spline Birfield joints with heavy-duty 4340 chromoly axle shafts to provide a significantly stronger front drivetrain solution for modified Land Cruiser 79 Series vehicles.

The Longfield Birfields are manufactured from chromoly steel and precision polished to remove imperfections that could create stress risers. Their internal components are manufactured from 4340 chromoly steel and dual heat-treated for increased strength.

The axle shafts are also manufactured from 4340 chromoly steel, providing a complete high-strength axle and Birfield package rather than upgrading only one component of the front drivetrain.

Application: Toyota Land Cruiser LC79 / 79 Series 1999-on

Birfield Specification: Longfield LC79 Gun-Drilled 30-Spline

Hub Compatibility: Suitable for both automatic and manual locking hubs

Toyota Land Cruiser 79 Series Compatibility

Trail-Gear lists this Super Set specifically for the Toyota Land Cruiser LC79 from 1999 onward.

Important: if the vehicle has had a previous axle conversion, hub conversion or other drivetrain modification, the existing components should be checked before ordering.

30-Spline Longfield Birfield Upgrade

The LC79 Super Set uses 30-spline Longfield Birfields together with matching heavy-duty chromoly axle shafts.

A stronger spline interface and high-strength chromoly construction make the kit particularly suitable for Land Cruisers subjected to increased drivetrain loads from:

• Larger off-road tyres
• Front differential lockers
• Low-range gearing
• Engine performance upgrades
• Technical off-road driving
• Heavy touring and expedition loads
• Commercial and working vehicle applications

4340 Chromoly Construction

Longfield uses high-strength chromoly steel throughout the critical drivetrain components of this Super Set.

• Birfield housing manufactured from forged 4340 chromoly steel
• Birfield internal components manufactured from 4340 chromoly steel
• Birfield internals dual heat-treated for increased strength
• Axle shafts manufactured from 4340 chromoly steel
• Birfield components precision polished to reduce imperfections and stress risers

The combination of material strength, heat treatment and precision finishing is designed to improve resistance to torsional loading and shock loads encountered during demanding 4x4 use.

Gun-Drilled Birfield Design

Each Longfield LC79 Birfield is gun drilled through the centre to create an internal grease passage.

An M8 grease zerk is fitted at the end of the stub shaft, allowing grease to pass directly through the centre of the Birfield and into its internal components.

This makes routine servicing significantly easier because the front axle does not need to be dismantled simply to lubricate the Birfield joint.

M8 Grease Zerk for Easy Servicing

The grease fitting at the end of the stub shaft allows fresh grease to be delivered directly to the Birfield internals.

This provides several practical advantages:

• Quicker routine servicing
• No need to dismantle the entire axle simply to lubricate the Birfield
• Easier maintenance after water, mud or demanding off-road use
• Improved access for regular preventative maintenance

Machined Spline Saver

The Longfield LC79 Birfield incorporates the Machined Spline Saver near the stub-shaft splines.

This shallow machined relief is designed to eliminate or reduce stress concentrations caused by grooving from the spline-cutting process.

The spline groove area can become a high-stress point on a heavily loaded Birfield stub shaft. Longfield's Machined Spline Saver is designed to reduce this concentration of stress and improve durability.

Dual Heat-Treated Birfield Internals

The internal components of the Longfield Birfields are manufactured from 4340 chromoly steel and then dual heat-treated.

The heat-treatment process is intended to produce the combination of hardness, strength and durability required for components exposed to heavy shock and torsional loads.

ABS Tone Rings Included

The complete LC79 Super Set includes ABS tone rings.

This is particularly important for ABS-equipped Land Cruiser applications because the wheel-speed sensors require the correct tone-ring signal for ABS operation.

The rings are supplied as part of the complete Super Set, avoiding the need to source separate tone rings during installation.

Automatic & Manual Locking Hub Compatibility

Trail-Gear specifically states that this LC79 kit works with both automatic and manual locking hubs.

This provides broader compatibility across different Land Cruiser 79 Series configurations and vehicles that have previously been converted from one locking-hub arrangement to another.

Technical Specifications

Performance Benefits

• Complete front Birfield and axle upgrade
• 30-spline Longfield Birfield configuration
• 2 × heavy-duty gun-drilled Birfield joints
• 2 × heavy-duty 4340 chromoly axle shafts
• Forged 4340 chromoly Birfield housings
• 4340 chromoly Birfield internals
• Dual heat-treated internal components
• Precision-polished components to reduce stress risers
• Machined Spline Saver at the stub-shaft spline area
• Gun-drilled grease passage for easier servicing
• M8 grease fittings
• ABS tone rings included
• Extended drive-flange dust caps included
• Compatible with automatic and manual locking hubs
• Designed for demanding off-road use

Ideal for Modified Toyota Land Cruiser 79 Series

The front axle drivetrain is subjected to significantly greater loads when a Land Cruiser is modified beyond its original specification.

The Longfield LC79 Super Set is particularly relevant for vehicles running:

• Larger-diameter tyres
• A front differential locker
• Reduced gearing
• High-torque diesel engine upgrades
• Heavy-duty commercial equipment
• Winch bumpers and additional front axle load
• Expedition equipment
• Regular technical off-road use

Upgrading both the Birfields and axle shafts together provides a properly matched front drivetrain package rather than simply moving the weak point from one standard component to another.

Suitable for Working & Expedition LC79 Builds

The Toyota Land Cruiser 79 Series is frequently used as a working, expedition and remote-area vehicle where drivetrain reliability is particularly important.

The Longfield Super Set is suitable for builds where the front axle may be exposed to repeated high-load operation from:

• Commercial use
• Heavy payloads
• Towing
• Remote-area travel
• Rock crawling
• Mud and technical terrain
• Large tyre conversions
• Engine torque increases

What’s Included

• 2 × Longfield LC79 Gun-Drilled 30-Spline Birfield Joints
• 2 × Longfield 4340 Chromoly Front Axle Shafts
• ABS Tone Rings
• Extended Drive-Flange Dust Caps

Installation & Fitment Notes

• Designed for Toyota Land Cruiser LC79 / 79 Series 1999-on
• Front axle application
• Compatible with automatic locking hubs
• Compatible with manual locking hubs
• Check existing axle components if the vehicle has previously been modified
• Inspect axle seals, bearings and hub components while the front axle is dismantled
• Use the correct high-quality Birfield grease during assembly
• Use the M8 grease zerk for routine future servicing
• Confirm correct ABS tone-ring installation on ABS-equipped vehicles
• Professional installation is recommended where appropriate

Why Replace Both Birfields & Axles Together?

A front axle system is only as strong as its weakest component.

Fitting stronger Birfields while retaining heavily worn or standard axle shafts can simply transfer the drivetrain load to another weak point.

The Longfield LC79 Super Set provides a matched package containing both heavy-duty Birfields and 4340 chromoly axle shafts, making it particularly suitable for complete front axle upgrades.

Maintenance

The gun-drilled Birfield design simplifies ongoing maintenance.

Fresh grease can be introduced through the M8 grease fitting at the end of the stub shaft, allowing the internal components of the Birfield to be lubricated without complete axle disassembly.

For vehicles regularly exposed to water, mud, sand or heavy off-road conditions, periodic inspection and lubrication of drivetrain components is strongly recommended.

Warranty

Trail-Gear states that this product carries its 12-Month Limited Warranty.

The warranty applies to the original purchaser and begins on the purchase date. It covers eligible defects in materials or workmanship under normal conditions of use and service, subject to Trail-Gear's full warranty terms and exclusions.

The warranty does not cover labour costs associated with diagnosis, removal or reinstallation, and exclusions apply to misuse, lack of maintenance, improper installation, modification, competitive racing and other circumstances listed in Trail-Gear's warranty policy.

Frequently Asked Questions

Q1: Which vehicle does the Longfield LC79 30-Spline Super Set fit?
A: Trail-Gear lists the kit for the Toyota Land Cruiser LC79 / 79 Series from 1999 onward.

Q2: Is this suitable for current Toyota Land Cruiser 79 Series models?
A: Trail-Gear lists the LC79 application as 1999-current. OFM4x4 describes the application as 1999-on to avoid restricting the listing to a particular calendar year.

Q3: How many Birfields are included?
A: The complete Super Set contains 2 Longfield LC79 gun-drilled 30-spline Birfield joints.

Q4: How many axle shafts are included?
A: The complete kit contains 2 heavy-duty 4340 chromoly front axle shafts.

Q5: Are the Birfields 30-spline?
A: Yes. This is the Longfield LC79 Gun-Drilled 30-Spline Super Set.

Q6: What are the Birfield housings made from?
A: The Birfield housings are manufactured from forged 4340 chromoly steel.

Q7: What are the Birfield internals made from?
A: The internals are manufactured from 4340 chromoly steel and dual heat-treated for increased strength.

Q8: What are the axle shafts made from?
A: The axle shafts are manufactured from 4340 chromoly steel.

Q9: What does gun drilled mean?
A: A grease passage is drilled through the centre of the Birfield, allowing grease to pass from the M8 grease fitting directly into the internal joint components.

Q10: Where is the grease fitting located?
A: An M8 grease zerk is fitted at the end of the Birfield stub shaft.

Q11: What is the Machined Spline Saver?
A: It is a shallow machined relief near the stub-shaft splines designed to reduce stress concentrations caused by the spline-machining process.

Q12: Are ABS tone rings included?
A: Yes. Trail-Gear specifically states that ABS tone rings are included with the LC79 Super Set.

Q13: Are extended drive-flange dust caps included?
A: Yes. Extended drive-flange dust caps are included.

Q14: Does the kit work with manual locking hubs?
A: Yes. Trail-Gear specifically states that the kit works with manual locking hubs.

Q15: Does it work with automatic locking hubs?
A: Yes. Trail-Gear states that it is compatible with both automatic and manual locking hubs.

Q16: Is this suitable for larger tyres?
A: The heavy-duty 4340 chromoly construction makes the kit particularly relevant for modified vehicles running larger tyres and increased drivetrain loads.

Q17: Is it suitable for a Land Cruiser 79 with a front locker?
A: Yes. Stronger Birfields and axle shafts are particularly useful when a front differential locker increases drivetrain loading during off-road use.

Q18: Is the kit suitable for high-torque engine upgrades?
A: Yes. The chromoly drivetrain components are well suited to applications where engine modifications increase torque transmitted through the front axle.

Q19: Do I need to remove the axle to grease the Birfields?
A: Routine Birfield lubrication is simplified by the gun-drilled design and M8 grease fitting, allowing grease to be fed directly through the stub shaft into the joint.

Q20: What is included with the complete kit?
A: The Super Set includes 2 Longfield LC79 gun-drilled 30-spline Birfields, 2 Longfield 4340 chromoly front axle shafts, ABS tone rings and extended drive-flange dust caps.

Q21: What warranty does this product carry?
A: Trail-Gear states that this product carries its 12-Month Limited Warranty for the original purchaser, subject to the manufacturer's full warranty terms and exclusions.

Why Buy from OFM4x4.CO.UK

• Genuine Longfield / Trail-Gear drivetrain components
• Heavy-duty Toyota Land Cruiser 79 Series axle upgrades
• Complete matched Birfield and axle shaft Super Set
• 30-spline Longfield drivetrain components
• 4340 chromoly construction
• Technical assistance with Toyota Land Cruiser drivetrain upgrades
• Supporting axle, differential and off-road drivetrain components available
• UK-based customer service