Longfield 30-Spline Gun-Drilled Birfield & Axle Kit for Toyota Land Cruiser 80 Series

The Longfield FJ80 30-Spline Gun-Drilled Birfield & Axle Super Set is a complete heavy-duty front axle upgrade for the Toyota Land Cruiser FJ80 1990–1997 and Lexus LX450 1995–1997.

This complete Longfield Super Set includes 2 gun-drilled 30-spline Birfield joints and 2 heavy-duty 4340 chromoly front axle shafts, together with new FJ80 ABS tone rings and extended drive-flange dust caps.

The key difference between this 30-spline Super Set and the stock-style 24-spline FJ80 arrangement is the spline count at the Birfield-to-inner-axle connection. Factory FJ80 front axles use a 30-spline hub connection, 24-spline Birfield / inner axle connection and 30-spline differential connection. This Longfield Super Set upgrades the Birfield / inner axle connection to 30 splines, creating a stronger 30-spline-through arrangement.

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

Important fitment clarification: this kit is not restricted to a particular early or late FJ80 differential. Trail-Gear lists it for 1990–1997 Toyota Land Cruiser FJ80 and 1995–1997 Lexus LX450. The early-model difference concerns the short drive flanges used on some 1990–1993 vehicles.

Vehicle Compatibility

1990–1993 FJ80: these vehicles may use shorter factory drive flanges. The Longfield Birfield stub shafts incorporate dual snap-ring grooves to accommodate both short and long FJ80 drive-flange configurations, and extended drive-flange dust caps are supplied in the kit.

If you want to reuse the original Toyota grease caps on a 1990–1993 model fitted with short drive flanges, Trail-Gear specifies the taller Toyota drive flange P/N 43421-60040.

What Does “30-Spline” Mean?

The 30-spline designation refers to the Birfield-to-inner-axle spline connection.

The standard FJ80 front axle arrangement is commonly described as a 24-spline axle because it uses:

• 30 splines at the hub / drive flange side
• 24 splines at the Birfield-to-inner-axle connection
• 30 splines at the differential side

The Longfield 30-Spline Super Set replaces the stock-style 24-spline Birfield connection with a 30-spline connection.

The resulting layout is effectively:

• 30-spline hub side
• 30-spline Birfield / axle connection
• 30-spline differential side

This increases the diameter and spline engagement at the Birfield / axle interface and provides a stronger arrangement than the stock-style 24-spline configuration.

30-Spline Upgrade vs 24-Spline FJ80 Axle

The 30-spline Longfield kit is therefore the stronger upgrade where maximum front axle strength is the priority.

4340 Chromoly Construction

The Longfield FJ80 30-Spline Super Set uses heavy-duty chromoly construction throughout the critical drivetrain components.

• Forged 4340 chromoly Birfield housings
• 4340 chromoly Birfield internals
• Dual heat-treated Birfield internals
• 4340 chromoly front axle shafts
• Precision-polished Birfield components to reduce stress risers

This construction is designed to provide substantially greater resistance to torsional loading, shock loads and axle breakage under demanding off-road conditions.

Gun-Drilled Birfield Design

Each Longfield 30-Spline Birfield is gun drilled through the centre to provide a direct grease passage into the Birfield internals.

An M8 grease zerk is fitted at the end of the stub shaft. Grease can therefore be delivered directly through the Birfield without dismantling the front axle simply to lubricate the joint.

This makes routine servicing significantly easier than with a conventional sealed Birfield arrangement.

Machined Spline Saver

The Longfield Birfield stub shaft incorporates the Machined Spline Saver.

This shallow machined relief is positioned close to the stub-shaft splines to reduce stress concentrations created during spline machining.

Trail-Gear identifies the spline groove as a common failure point on Birfield stub shafts. The Machined Spline Saver is intended to reduce concentrated loading in this area.

Dual Snap-Ring Grooves

The Birfield stub shafts feature dual snap-ring grooves.

This allows the same Birfield design to work with both the short and long FJ80 drive-flange configurations used during production.

• Compatible with early short drive flanges
• Compatible with later long drive flanges
• Supports the full listed 1990–1997 FJ80 application

ABS & Non-ABS Compatibility

The Longfield 30-Spline Super Set includes new FJ80 ABS tone rings.

This allows installation on both:

• ABS-equipped FJ80 models
• Non-ABS FJ80 models
• Compatible Lexus LX450 applications

The supplied tone rings also eliminate the need to transfer potentially worn or damaged original tone rings from the factory Birfields.

1990–1993 Short Drive Flange Information

Some 1990–1993 Toyota Land Cruiser FJ80 models use short drive flanges.

The Longfield kit includes extended drive-flange dust caps to accommodate these early applications.

If the owner wants to reuse the original Toyota grease caps, Trail-Gear specifies the taller Toyota drive flange:

Toyota P/N 43421-60040

This is a drive-flange issue and is separate from the 30-spline upgrade at the Birfield-to-inner-axle connection.

Technical Specifications

Performance Benefits

• Complete 30-spline front Birfield and axle upgrade
• 2 × heavy-duty Longfield 30-spline Birfield joints
• 2 × heavy-duty 4340 chromoly axle shafts
• 30-spline Birfield / inner axle interface replaces the stock-style 24-spline connection
• Forged 4340 chromoly Birfield housings
• 4340 chromoly internals
• Dual heat-treated Birfield components
• 4340 chromoly axle shafts
• Increased resistance to twisting and shock loading
• Designed for demanding off-road use
• Suitable for larger tyres
• Suitable for locking differential applications
• Gun-drilled lubrication system simplifies maintenance
• Machined Spline Saver reduces stress concentration
• Dual snap-ring grooves support short and long drive flanges
• ABS and non-ABS compatible

Who Should Choose the 30-Spline Super Set?

The Longfield 30-Spline Super Set is the logical choice for Land Cruiser owners looking for the strongest Longfield FJ80 front axle configuration.

It is particularly relevant for vehicles fitted with:

• Large-diameter off-road tyres
• Front differential lockers
• Lower differential or transfer-case gearing
• High-torque diesel or petrol engine upgrades
• Heavy expedition equipment
• Winch bumpers and increased front axle load
• Vehicles regularly used for technical rock crawling or extreme off-road driving

The 30-spline Birfield / axle interface provides additional strength over the stock-style 24-spline connection while retaining the factory 30-spline differential-side and hub-side arrangement.

30-Spline vs Longfield 24-Spline Kit

Both Longfield FJ80 Super Sets use heavy-duty chromoly construction, gun-drilled Birfields, ABS tone rings, extended dust caps, dual snap-ring grooves and the Machined Spline Saver.

The major difference is the spline count where the inner axle engages with the Birfield:

What’s Included

• 2 × Longfield FJ80 Gun-Drilled 30-Spline Birfield Joints
• 2 × Longfield 4340 Chromoly Front Axle Shafts
• FJ80 ABS Tone Rings
• Extended Drive-Flange Dust Caps

Important Fitment Notes

• Fits Toyota Land Cruiser FJ80 1990–1997
• Fits Lexus LX450 1995–1997
• Provides a 30-spline Birfield / inner axle connection
• Differential-side spline remains compatible with the factory 30-spline FJ80 differential connection
• Compatible with ABS and non-ABS applications
• Dual snap-ring grooves accommodate short and long FJ80 drive flanges
• 1990–1993 short-drive-flange models can use the supplied extended dust caps
• To reuse OEM grease caps on 1990–1993 short-flange vehicles, use taller Toyota drive flange P/N 43421-60040
• Check the existing front axle configuration if the vehicle has previously been modified

Lifetime Warranty

Trail-Gear states that the Longfield FJ80 30-Spline Super Set carries its Lifetime Warranty.

The warranty covers eligible manufacturing defects and breakage during normal use for as long as the original purchaser owns the vehicle, subject to Trail-Gear's full warranty terms, exclusions and claim procedures.

The warranty applies to the original purchaser and is not transferable.

Frequently Asked Questions

Q1: How many Birfields are included?
A: The complete Super Set includes 2 Longfield FJ80 gun-drilled 30-spline Birfield joints.

Q2: How many axle shafts are included?
A: The kit includes 2 Longfield 4340 chromoly front axle shafts.

Q3: Does the 30-spline kit fit all 1990–1997 FJ80 models?
A: Trail-Gear lists the kit for Toyota Land Cruiser FJ80 models from 1990–1997. Early 1990–1993 vehicles may use short drive flanges, which are accommodated by the dual snap-ring grooves and supplied extended dust caps.

Q4: Does it fit a 1995 Land Cruiser 80?
A: Yes. Trail-Gear lists the complete 1990–1997 FJ80 range.

Q5: Does it fit the Lexus LX450?
A: Yes. Trail-Gear lists the Lexus LX450 from 1995–1997.

Q6: What is 30-spline on this kit?
A: The 30-spline designation refers principally to the upgraded Birfield-to-inner-axle connection. The kit uses a 30-spline arrangement through the hub, Birfield connection and differential side.

Q7: What spline arrangement does the standard FJ80 use?
A: The factory-style arrangement uses 30 splines at the hub, 24 splines at the Birfield-to-inner-axle connection and 30 splines at the differential side.

Q8: Is the 30-spline kit stronger than the 24-spline version?
A: Yes. The 30-spline version increases the spline count and shaft diameter at the Birfield / inner axle connection, eliminating the stock-style 24-spline section.

Q9: Do I need a different 30-spline differential?
A: No special differential conversion is specified by Trail-Gear. The FJ80 differential-side axle connection is already 30 spline. The upgrade is at the Birfield / inner axle interface.

Q10: Does the kit fit 1990–1993 models?
A: Yes. The Birfields have dual snap-ring grooves and the kit includes extended dust caps for vehicles using short drive flanges.

Q11: Can I reuse the OEM grease caps on a 1990–1993 FJ80?
A: Yes, but Trail-Gear states that vehicles with the short drive flanges need taller Toyota drive flanges P/N 43421-60040 to reuse the original grease caps.

Q12: Does the kit fit ABS-equipped vehicles?
A: Yes. New FJ80 ABS tone rings are included.

Q13: Does it fit non-ABS FJ80s?
A: Yes. Trail-Gear states that the kit can be installed on both ABS and non-ABS FJ80 applications.

Q14: What are the Birfield housings made from?
A: The Birfield housings are forged from 4340 chromoly steel.

Q15: What are the Birfield internals made from?
A: The internals are made from 4340 chromoly steel and dual heat-treated for increased strength.

Q16: What are the axle shafts made from?
A: The axle shafts are manufactured from 4340 chromoly steel.

Q17: What does gun drilled mean?
A: A grease passage is drilled through the centre of the Birfield so grease can pass from the M8 grease fitting directly into the joint.

Q18: What is the Machined Spline Saver?
A: It is a shallow machined relief near the stub-shaft spline area designed to reduce stress concentrations caused by spline machining.

Q19: Why are there dual snap-ring grooves?
A: They allow compatibility with both the short and long drive-flange configurations used across FJ80 production.

Q20: Is the 30-spline kit suitable for larger tyres and lockers?
A: Yes. The full 30-spline chromoly arrangement is particularly suited to demanding off-road vehicles running larger tyres, front lockers and increased drivetrain loads.

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

Q22: What is included with the complete Super Set?
A: The set includes 2 Longfield FJ80 gun-drilled 30-spline Birfields, 2 Longfield 4340 chromoly front axle shafts, FJ80 ABS tone rings and extended drive-flange dust caps.

Why Buy from OFM4x4.CO.UK

• Specialists in Toyota Land Cruiser drivetrain upgrades
• Genuine Longfield / Trail-Gear products
• Complete 30-spline front axle and Birfield upgrade
• Heavy-duty drivetrain solutions for modified Land Cruiser 80 Series vehicles
• 24-spline and 30-spline Longfield FJ80 options available
• Technical assistance with FJ80 fitment and drive-flange compatibility
• Supporting differential, axle and drivetrain upgrades available
• UK-based customer service