Longfield Chromoly Birfield & Axle Kit (24-Spline) – Toyota Land Cruiser 80 Series (301712-1-KIT)

Longfield 24-Spline Birfield & Axle Kit for Toyota Land Cruiser 80 Series

The Longfield 24-Spline Birfield & Axle Kit 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 heavy-duty 4340 chromoly front axle shafts and 2 Longfield 24-spline gun-drilled Birfield joints, together with new FJ80 ABS tone rings and extended drive-flange dust caps.

Longfield Birfields are engineered for demanding off-road use and are manufactured from high-strength chromoly steel. The Birfield housings are forged from 4340 chromoly, while the internal components are also manufactured from 4340 chromoly and dual heat-treated for increased strength.

Important fitment clarification: this kit is not restricted to an “early 24-spline front differential”. Trail-Gear lists the kit for 1990–1997 FJ80 models. The main early-model fitment difference is the short drive flange used on some 1990–1993 FJ80 vehicles.

The Longfield Birfield stub shafts include dual snap-ring grooves specifically to accommodate both short and long FJ80 drive-flange configurations.

Vehicle Compatibility

1990–1993 FJ80: these vehicles may use short drive flanges. The Longfield Birfields use dual snap-ring grooves to accommodate both short and long drive flanges, and the kit includes extended drive-flange dust caps.

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

What Does “24-Spline” Mean?

The 24-spline designation refers to the Longfield FJ80 Birfield / axle kit specification. It should not be interpreted as meaning that the vehicle must have a special early-model 24-spline front differential.

Trail-Gear lists this Super Set across the complete 1990–1997 FJ80 application, with the production difference being the short and long drive-flange arrangement rather than a stated early-only differential requirement.

4340 Chromoly Construction

The Longfield FJ80 Super Set is designed to provide substantially greater drivetrain strength than worn or standard factory axle 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 imperfections and stress risers

The stronger materials and heat-treatment process make the kit particularly suitable for vehicles running larger tyres, differential lockers and demanding off-road conditions.

Gun-Drilled Birfield Design

Each Longfield Birfield is gun drilled through the centre to create a direct grease passage into the Birfield internals.

An M8 grease zerk is fitted at the end of the stub shaft, allowing grease to be delivered directly through the Birfield without having to completely dismantle the front axle simply to service the joint.

This greatly simplifies routine Birfield lubrication and maintenance.

Machined Spline Saver

The Longfield Birfield stub shaft incorporates a Machined Spline Saver.

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

Trail-Gear identifies the spline groove area as a common Birfield stub-shaft failure point, so the Machined Spline Saver is designed to reduce stress concentration in this area.

Dual Snap-Ring Grooves

Each Longfield Birfield stub shaft features dual snap-ring grooves.

This allows the same Birfield design to accommodate the different drive-flange configurations used throughout FJ80 production.

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

ABS & Non-ABS Compatibility

The kit includes a set of new FJ80 ABS tone rings.

Trail-Gear specifically states that this allows the Longfield FJ80 Super Set to be installed on both:

• ABS-equipped FJ80 models
• Non-ABS FJ80 models

This also removes the need to reuse worn or damaged original ABS tone rings from the existing 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 so the supplied Birfields can be used with these early short-flange configurations.

If the owner prefers to retain the factory Toyota grease caps, Trail-Gear specifies fitting the taller Toyota drive flange:

Toyota P/N 43421-60040

This is a drive-flange difference and should not be confused with the front differential spline count.

Technical Specifications

Performance Benefits

• Complete front axle and Birfield upgrade
• 2 × heavy-duty chromoly axle shafts
• 2 × heavy-duty Longfield Birfield joints
• Forged 4340 chromoly Birfield housings
• 4340 chromoly internal components
• Dual heat-treated Birfield internals
• 4340 chromoly axle shafts
• Improved resistance to twisting and shock loading
• Designed for demanding off-road use
• Suitable for vehicles running larger tyres
• Suitable for vehicles fitted with locking differentials
• Gun-drilled lubrication system simplifies maintenance
• Machined Spline Saver reduces stress concentration at the stub shaft
• Dual snap-ring grooves support short and long drive flanges
• Compatible with ABS and non-ABS vehicles

Ideal for Modified Land Cruiser 80 Series

The factory front Birfields and axle shafts can become a weak point as drivetrain load increases.

The Longfield Super Set is particularly relevant for Land Cruiser 80 Series vehicles fitted with:

• Larger off-road tyres
• Front differential lockers
• Lower gearing
• High-torque engine modifications
• Heavy expedition equipment
• Winch bumpers and additional front axle load
• Vehicles regularly used in technical off-road conditions

What’s Included

• 2 × Longfield FJ80 Gun-Drilled 24-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
• Compatible with ABS and non-ABS FJ80 applications
• Birfield stub shafts use dual snap-ring grooves for short and long drive flanges
• 1990–1993 short-drive-flange models can use the included extended dust caps
• To retain OEM grease caps on 1990–1993 short-flange vehicles, use Toyota taller drive flange P/N 43421-60040
• Do not determine compatibility solely from a claimed front differential spline count
• Check the existing front axle configuration if the vehicle has previously been modified

Warranty

Trail-Gear states that this product is covered by its 12-Month Limited Warranty for the original purchaser, subject to the manufacturer's warranty terms, exclusions and installation requirements.

Frequently Asked Questions

Q1: How many Birfields are included?
A: The complete kit includes 2 Longfield FJ80 gun-drilled 24-spline Birfield joints.

Q2: How many axle shafts are included?
A: The complete kit includes 2 heavy-duty 4340 chromoly front axle shafts.

Q3: Does this kit only fit early Land Cruiser 80 models?
A: No. Trail-Gear lists the Longfield FJ80 24-Spline Super Set for Toyota Land Cruiser FJ80 models from 1990–1997.

Q4: Does my front differential need to be 24-spline?
A: Trail-Gear does not specify this kit as requiring a special early-model 24-spline front differential. The manufacturer's application is the FJ80 front axle, with the main production difference being short versus long drive flanges.

Q5: What does 24-spline refer to?
A: It is the Longfield FJ80 Birfield / axle kit specification and should not be interpreted as an early-model-only front differential requirement.

Q6: Does it fit a 1995 Toyota Land Cruiser 80?
A: Yes. Trail-Gear lists the kit for FJ80 models from 1990–1997.

Q7: Does it fit 1990–1993 models?
A: Yes. The Birfield stub shafts have dual snap-ring grooves for short and long drive flanges, and extended dust caps are included for early short-flange applications.

Q8: What is different on 1990–1993 FJ80 models?
A: Some early models use short drive flanges. This is the early-model fitment difference identified by Trail-Gear.

Q9: Can I reuse the OEM grease caps on a 1990–1993 FJ80?
A: Yes, but Trail-Gear states that short-drive-flange models require taller Toyota drive flanges P/N 43421-60040 to reuse the OEM grease caps.

Q10: Does this kit fit ABS-equipped Land Cruiser 80 models?
A: Yes. New FJ80 ABS tone rings are included.

Q11: Does it also fit non-ABS vehicles?
A: Yes. Trail-Gear states that the kit can be installed on both ABS and non-ABS FJ80 applications.

Q12: Does it fit the Lexus LX450?
A: Yes. Trail-Gear lists the Lexus LX450 from 1995–1997.

Q13: What are the Birfield housings made from?
A: The Birfield housings are forged from 4340 chromoly steel.

Q14: What are the Birfield internals made from?
A: The internal components are manufactured from 4340 chromoly steel and dual heat-treated for increased strength.

Q15: What are the axle shafts made from?
A: Both front axle shafts are manufactured from 4340 chromoly steel.

Q16: What does gun drilled mean?
A: A grease passage is drilled through the centre of each Birfield so grease can be delivered directly into the internal components through the M8 grease fitting.

Q17: What is the Machined Spline Saver?
A: It is a shallow machined relief near the stub-shaft splines designed to reduce stress concentration at a common Birfield failure point.

Q18: Why are there dual snap-ring grooves?
A: The dual grooves allow the Birfield stub shaft to accommodate both the short and long drive-flange configurations used across FJ80 production.

Q19: Is this suitable for larger tyres and lockers?
A: Yes. The 4340 chromoly construction and upgraded Birfield design make the kit particularly suitable for modified Land Cruiser 80 Series vehicles used in demanding off-road conditions.

Q20: What is included with the complete set?
A: The set includes 2 Longfield FJ80 gun-drilled 24-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 front axle and Birfield upgrade kit
• Heavy-duty drivetrain solutions for modified Land Cruiser 80 Series vehicles
• Technical assistance with FJ80 fitment and drive-flange compatibility
• Supporting differential, axle and drivetrain upgrades available
• UK-based customer service