FORMULA, SUPERPRO Diff Drop Kits for TOYOTA FJ CRUISER

A diff drop kit lowers the front differential on an independent front suspension 4WD, reducing the CV joint angles that a suspension lift increases. When an IFS 4WD is lifted, the wheels move down relative to the body, but the front differential stays bolted to the chassis. The CV shafts then run at a steeper angle, which can increase wear on the CV joints and boots. Lowering the differential brings those angles back closer to standard. Use the vehicle search to find diff drop kits to suit your TOYOTA FJ CRUISER.

What Does a TOYOTA FJ CRUISER Diff Drop Kit Do?

On an IFS 4WD, the front differential is mounted to the chassis, and a CV shaft runs from each side of the differential out to the wheel hub. Each CV shaft has a joint at each end, which lets it transmit drive while the suspension moves up and down and the steering turns.

A diff drop kit uses spacers or replacement brackets to lower the differential's mounting points by a set amount. With the differential sitting lower, the CV shafts run at a flatter angle between the differential and the wheels at the lifted ride height. That reduces the operating angle of the CV joints, which is designed to reduce the load on the joints and the stress on the CV boots.

A diff drop kit does not raise the vehicle. It is a supporting part fitted alongside a lift to manage the driveline angles the lift creates.

How Does a Lift Change CV Angles on an IFS TOYOTA FJ CRUISER?

CV joints are designed to work within a range of angles. At standard ride height, the CV shafts sit close to level, and the joints operate comfortably in the middle of their range as the suspension moves.

When an IFS 4WD is lifted, the suspension is extended, so the wheel hubs sit lower relative to the chassis and differential. The CV shafts now slope downward from the differential to the wheels at a steeper angle. As the suspension extends further on rough ground, the angle increases again. The CV joints spend more of their time near the edge of their range, where they generate more heat and wear faster, and the rubber boots are stretched and flexed further.

The larger the lift, the steeper the angles become. That is why the need for a diff drop increases with lift height.

Signs of Excessive CV Angle on Your TOYOTA FJ CRUISER

Possible signs include a clicking or knocking noise from the front wheels when turning, particularly in four-wheel drive at full steering lock. CV boots that split or tear soon after a lift, or grease flung around the inside of the wheel or onto the suspension, can also point to the joints and boots working at steep angles. A vibration under acceleration in four-wheel drive is another possible sign. These symptoms can also come from worn CV joints or damaged boots, so an inspection is recommended.

Does Your TOYOTA FJ CRUISER Need a Diff Drop With a 2 Inch Lift?

Often not at around 2 inches, or 50mm, although it varies by vehicle and setup. Many IFS 4WDs can run a modest lift with the CV angles still within an acceptable range, particularly when the vehicle spends most of its time in two-wheel drive on sealed roads.

Diff drops are more commonly recommended as lift height increases, and on vehicles that spend a lot of time in four-wheel drive, where the CV joints are under load. The vehicle's front suspension design, the exact lift height, how the suspension is set up and how the vehicle is used all affect the answer. Some lift kits list a diff drop as recommended hardware for a particular vehicle and lift height. Get advice for your setup before deciding.

Does a Diff Drop Affect TOYOTA FJ CRUISER Ground Clearance?

Slightly, under the front differential itself. Because the diff drop lowers the differential, the differential housing sits closer to the ground than it would on the same lifted vehicle without a diff drop. In most setups, the lift raises the vehicle by more than the diff drop lowers the differential, so the net clearance under the differential is still greater than standard, but the exact change depends on the setup.

Lowering the differential can also affect the front cross brace that runs beneath it on many IFS 4WDs, which may need to be lowered or replaced to maintain clearance between the brace and the differential.

How Does a Diff Drop Fit With the Rest of a TOYOTA FJ CRUISER Lift?

A diff drop is one of several supporting parts that may be needed when an IFS 4WD is lifted, depending on the vehicle and lift height. Alongside the lift itself, which usually includes springs, struts or shocks, a lifted IFS vehicle may need upper control arms to restore camber and caster, sway bar relocation or longer links to keep the sway bar working correctly, and brake line or ABS wiring extensions so nothing is stretched at full droop.

Where a diff drop is fitted, a brace drop spacer or replacement front brace may be needed to clear the lowered differential. Planning these parts together, rather than adding them one at a time after problems appear, makes for a more complete and reliable setup.

Why Only the Front Differential?

Diff drop kits are a front-end part for IFS 4WDs. On most 4WDs, the rear differential is part of a solid rear axle, which moves with the wheels as the suspension travels. Because the rear axle shafts run inside the axle housing, the rear driveline does not have CV shafts running at steeper angles after a lift in the same way. The rear driveline can still be affected by a lift, but through the tailshaft and its universal joints rather than the differential position.

Solid front axle 4WDs also do not use diff drop kits, because the front differential is part of the axle and moves with the wheels.

What's Involved in Fitting a TOYOTA FJ CRUISER Diff Drop Kit?

Diff drop kits generally bolt in using the differential's existing mounting points, but fitting involves supporting the front differential while its mounts are undone, then lowering it onto the new spacers or brackets. Depending on the vehicle, the CV shafts, front tailshaft, breather lines and wiring may need to be checked for clearance or adjusted so nothing is stretched or fouling once the differential sits lower.

Fasteners must be tightened to the manufacturer's torque specification, and the work should be done with the vehicle securely supported on rated stands. Because the job involves supporting and repositioning a heavy driveline component, professional installation is recommended.

Checking the TOYOTA FJ CRUISER Driveline After Fitting

After a diff drop is fitted, check the CV boots for contact with suspension or steering components through full suspension travel and full steering lock. Check the front tailshaft angle and clearance, the differential breather line and any wiring or hoses near the differential.

Recheck the differential mounting bolts after the first few hundred kilometres and again after the first off-road trip, since fasteners can settle. Inspecting the CV boots regularly afterwards, especially after rough tracks, catches any damage before dirt and water reach the joints.

TOYOTA FJ CRUISER Diff Mount Bushes and Wear

On many IFS 4WDs, the front differential is mounted through rubber bushes that isolate vibration from the driveline. These bushes wear over time, and a worn diff mount can let the differential move under load, which can cause clunks when taking off or changing between drive and reverse in four-wheel drive. When fitting a diff drop kit, it is worth inspecting the differential mount bushes while the mounts are accessible, and replacing them if they are cracked or worn.

Get the Right TOYOTA FJ CRUISER Diff Drop Kit with Formula 4x4

Diff drop kits are part of our suspension parts range for lifted IFS 4WDs.

Start by confirming your lift height and how often the vehicle is used in four-wheel drive, and check whether your lift kit recommends a diff drop for your vehicle. Consider whether the front brace will need to be lowered or replaced at the same time. Search by your TOYOTA FJ CRUISER to find diff drop kits to suit your TOYOTA FJ CRUISER. If you are unsure whether your setup needs one, contact the Formula 4x4 team.