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Toyota SUV Spotter's Guide - 4Runner Facts

Posted in Features on September 1, 2014 Comment (0)
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Toyota 4Runners weren’t the first sport utility vehicles (SUV) to hit the planet, but they have definitely made their mark off the pavement, along with their senior sibling, the Land Cruiser. The 4Runner was introduced in 1984 and has survived in the Toyota product line for over three decades to the current fifth-generation model, always being built in Tahara, Japan. These reliable vehicles have changed with the demands of modern consumers and with the advances of automotive technology, but they remained patterned after the sturdy construction of the venerable Land Cruiser line.

Similar to the Toyota truck line, the 4Runner has been offered in numerous configurations over the years, including both 2WD and 4WD models in some generations. SR5 and Limited models often got many of the aesthetics and mechanical upgrades, to include lower axle gearing, lockers, and various versions of 4WD and traction-control systems. While other SUVs have morphed to unibody construction or slipped to AWD crossover designation, the 4Runner maintains reinforced body-on-frame construction. Here we’ll take a look at the evolution of the 4WD 4Runner as it has progressed through five generations of body styles and models.

First Generation (1984 to 1989)
The earliest 4Runners built from 1984 to 1989 had squarish fenderwells. Unfortunately, in some ways, these were the only years that allowed you to remove the top without reverting to the use of a reciprocating saw. These original versions were all two-door versions with the shortest 103-inch wheelbase.

Over the past 30 years, Toyota has offered three styles of front suspensions. Early U.S. models up through 1985 came equipped with a front straight axle and leaf springs. Beginning in 1986, Toyota converted to their Hi-Trac independent front suspension (IFS) using A-arms and upper torsion bars on the 4Runners. Straight axle and torsion IFS 4Runners used recirculating ball steering boxes. The straight-axle trucks had a push/pull–style draglink, while the IFS trucks had a cross-link and idler arm assembly. Early 4Runners, like all Toyota trucks were equipped with a traditional leaf-spring rear suspension.

From its humble beginnings in 1984, the 4Runner has proven itself to be a top-notch off-road SUV, and has lent itself well to modifications. The aftermarket is ripe with upgrade offerings since the 4Runner has proven itself a popular vehicle for backcountry exploring.

Over the years, Toyota has offered a number of engines in 4Runners. 2.4L I-4 engines were used in the early models through 1995. Both carbureted (22R) and multi-port fuel injection (22RE) versions were offered. 1988 and newer, have been fuel injected. To increase engine power until they could introduce a V-6 engine, Toyota sold a turbo version 22R-TE in some SR5 models in 1986 and 1987. In 1988, the 3.0L V-6 3VZ-E engine was introduced.

4Runners started life with the basic five-speed manual transmission. But automatic transmissions have been available in most all 4Runners as an added option.

Toyota has varied the axle gearing over the years to accommodate the various engines, transmissions, and tire sizes. Gearing in first-generation 4Runners was often either 4.10:1 or 4.30:1. All early 4Runners were equipped with disc-drum brake systems and would remain that way through 2002.

Through the years, Toyota has used several transfer case designs in their 4Runners. The high range ratio is 1:1 in all these Toyota transfer cases. Low range ratios have mostly been either 2.28:1 or 2.57:1. Typically pre-’96 four-cylinder 4Runners with manual transmissions used the gear driven 2.28:1 ratio. The four-cylinder turbo, 3.0L V-6, and some automatics used the 2.57:1 or 2.66:1 chain drive case. Pre-’96 4Runners have a passenger-side front drive output, while the later models have a driver-side output.

In the early years, Toyota only offered traditional manual locking front hubs to engage 4WD. Some mid to late 1980s 4Runners had automatic locking hubs that worked well when new, but tended to fail after some years or a large number of use cycles.

Build parts are, understandably, most abundant for the first-generation 4Runners. This is especially true for the straight axle versions as they are prized for hard-core articulation on tough trails. However, solid axle swaps on the torsion bar IFS has been cookie-cutter duplicated for nearly 20 years now, so swaps are relatively straight-forward.

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Second Generation (1990 to 1995)
Starting in 1990, Toyota returned to the rounded fenderwells on the 4Runner, similar to the earlier Toyota trucks. Most of these 103.3-inch wheelbase models with full steel body were four-door versions through the 1995 model year, and designed to carry up to five passengers.

The rear leaf springs were dropped in favor of a four-link coil spring linked suspension in 1990. To date, all following 4Runners have used a four-link with Panhard bar. Despite the relatively short links used, the system works well and can be further enhanced with short lift springs to raise the tail a few inches.

The 22RE and 3VZ-E engines would serve duty for the second-generation 4Runners through 1995. In general, all of the engines used in the 4Runner have been extremely reliable, and long-lasting. The one exception has been some of the 3.0L V-6 3VZ-E engines. Some of these suffered from factory defective head gaskets, and many were recalled to dealers for replacement after the defect was discovered. Some factory sealed engines lasted for hundreds of thousands of miles without an issue. Meanwhile, others developed low-mileage leaks, and sometimes the issue reoccurred after a hasty dealer repair. These days, it’s often easy to find clean second-generation 4Runners cheap with a blown 3VZ-E engine.

The second-generation 4Runner continued to use torsion bar independent front suspension but dropped the use of rear leaf springs in favor of a four-link coil spring linked suspension. The coils offered a more comfortable ride, but reasonable lifts were relatively easy to do. This one’s been converted with a straight front axle.

Axle gearing in second-generation 4Runners varied across the years with ratios of 4.10:1, 4.30:1, 4.56:1, and 4.88:1. Toyota introduced rear-wheel antilock brakes in 1990 models and in 1994, four-wheel antilock brakes were offered as an option on all V-6 models.

The 4WDemand system was optional starting in 1990, and allowed shift-on-the-fly 4WD. The 4WDemand system used fixed hubs at the wheel hub such that the front axle shafts and CV joints were constantly turning. A vacuum actuated system engaged the front axle drive when the transfer case was shifted to 4WD.

The second-generation 4Runners have the early IFS system with limited travel capability in stock form. Many of these models on the trail have eventually been swapped to a solid axle up front. These are great builders on a usable wheelbase and maintain the “mini-truck” size that started to disappear with newer models. Beware of the 3.0L V-6 pitfalls, or use this Achilles’ heel to score a clean rolling rig to work on.

Third Generation (1996 to 2002)
The next 4Runner introduced for 1996, and offered until 2002, featured a larger body sitting on a new chassis, and the wheelbase was stretched 2 inches. This was the first year that the 4Runner would not share the same body panels or frame with its companion truck model.

With the introduction of the Tacoma line and the third-generation 4Runner in 1996, the front suspension was swapped over to a coil spring independent double-wishbone setup. Front suspension travel increased 25 percent or more with this change. Toyota has stayed with this basic style of suspension up to the current models. Most all IFS models came with gas-charged shocks and stabilizer bars. Beginning with the 1996 models, the steering was changed over to power-assisted rack-and-pinion.

Larger four- and six-cylinder engines were introduced in the third-generation 4Runner. These were the 2.7L 3RZ-FE I-4 (until 2000) and the 3.4L 5VZ-FE V-6 multi-cam, multi-valve engines. Manual transmissions were last offered in the 2000 models. Starting in 2001, all 4Runners with the 3.4L V-6 engine were equipped with a four-speed automatic transmission.

Axle gear ratios were available to handle the different drivetrains and tire sizes, with ratios of 3.91:1, 4.10:1, 4.30:1, and 4.56:1. Also, in 2001, the brake booster was changed to hydraulic assisted. Toyota had been offering an electric locking differential in its FZJ-80 Land Cruiser line since 1993. This proven differential style was then made available as an option on some third-generation 4Runners through 2000. The locker is engaged using a dash-mounted switch.

Toyota offered new engines in the ’96 4Runner models. There was the new 2.7L I-4 and the more powerful 3.4L V-6. Enthusiasts finally had a robust and reliable V-6 to choose. The earlier 3.0L V-6 offered a decent improvement in horsepower over the 22RE, but not a lot more torque, and it was certainly less reliable and more complicated. Along with the new V-6, Toyota offered a Toyota Racing Development (TRD) supercharger kit with the option of dealer installation and warranty, to really wake up the V-6 engine.

In 1999, Toyota introduced their multi-mode 4WD system on the Limited models. The full-time all-wheel-drive system has 2WD capability and was designed to tackle all driving surfaces, including dry pavement. Vehicle Skid Control was included with traction control.

Body size and weight bloated a bit in the third generation, but these models make greater exploring rigs and offer improved interior comfort, along with an improved front suspension. The 3.4L V-6 is an excellent performer, and you can have your choice of automatic or manual transmission in the 2000 and earlier year models.

Fourth Generation (2003 to 2009)
Toyota made its most drastic body changes to date when it introduced the fourth-generation 4Runner, which was produced from 2003 through 2009. The 4Runner grew once again to become wider and longer with a 109.8-inch wheelbase.

Some fourth- and fifth-generation 4Runners came equipped with the X-Relative Absorber System (X-REAS) that linked the damping of shocks diagonally on the vehicle using hydraulic hoses). It was used to counteract vehicle sway, but can be expensive to repair or replace with factory components.

The fourth-generation models from 2003 to 2009 grew even larger to a nearly 110-inch wheelbase, and Toyota made the 4Runner more car-like while eyeing off-road capabilities.

With the larger, heavier fourth-generation 4Runner, engine sizes were again increased with the 4.0L 1GR-FE V-6 (first all-aluminum engine in a Toyota truck) and 4.7L 2UZ-FE iForce V-8. More power was added to the V-8 in 2005 when it jumped from 235 to 270 hp with the addition of variable valve timing. While the early 4.0L V-6 engines had a four-speed automatic, the V-8 engines used a five-speed automatic. The last year the V-8 was offered was in 2009.

Also, beginning in 2003, all 4Runners were equipped with Hill-start Assist Control (HAC) to prevent rolling backward on steep hills and Downhill Assist Control (DAC) that modulates the brakes on steep downhill inclines. This can prevent skidding, but also gives the driver less braking control. A console-mounted switch allows the driver to disable the feature. In 2005, the V-6 engine was upgraded to a five-speed automatic from the previous four-speed version.

Axle gearing in the 2003 and 2004 models could be either 3.73:1 or 3.91:1, but later years all simplified to the 3.73:1 ratio.

In 2005, Toyota implemented a Vehicle Stability Control (VSC) system that incorporated an Auto-LSD function, with Toyota stating this eliminated the need for a mechanical limited-slip rear differential. For 2008, Toyota added a VSC cut-off switch. The Trail Edition package in 2009 thankfully saw the return of a locking rear differential, along with Active Traction Control (A-TRAC).

Starting in 2003, Toyota gave the SUV disc brakes on all four corners and a Torsen torque-sensing limited-slip center differential in the transfer case. This system works automatically to bias torque front/rear as needed for traction, or the driver can select a locking mode to redistribute torque manually. The V-6 models used the Multi-Mode 4WD system, while the V-8 models came equipped with full-time 4WD.

The fourth-generation Toyota SUV gained more weight and length over its predecessor. It’s still a comfortable 4WD, but modern amenities and safety features have made it more complicated.

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Fifth Generation (2010 to Present)
The current generation 4Runner was introduced for model year 2010. Wheelbase remained unchanged from the previous model and it continues to be built as a body-on-frame vehicle with ever more creature comforts and technology enhancements. Fifth-generation 4Runners came optionally equipped with the Kinetic Dynamic Suspension System (KDSS), a traction control system that increases articulation and decreases body roll.

The 4.0L engine is still in use today, utilizing a 24-valve setup with dual independent variable valve timing which added 34 hp starting in 2010 as compared to the previous V-6 version. All fifth-generation 4Runners have come with 3.73:1 ring-and-pinion sets.

If you’re in the market for a 4Runner, you’ve got three decades of model choices to choose from with a dizzying array of body types, suspensions, drivetrains, and traction/stability aids to choose from. The early models were essentially utilitarian trucks with an extended cab area, and later models offer a quiet, car-like comfort while still offering the 4WD durability of a steel frame SUV.

The latest incarnation of the 4Runner is the fifth-generation SUV introduced in the 2010 model year. It shares the same platform as the FJ Cruiser. Wheelbase from the previous generation to today sits at 109.8 inches.

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