Table of Contents:

• Overview
• Body
• Wheelbase
• Front Suspension
• Rear Suspension
• Engines
• Transmissions
• Transfer Cases
• Brakes
• Axle Gear Ratios

Overview:

Toyota sent the first 4WD mini-truck to the shores of the United States in 1979. Small trucks were already popular, but prior to this no manufacturer had made 4WD minis. If you wanted a 4WD, you had to convert your 2WD on your own or purchase a kit from one of the aftermarket companies, like Low Manufacturing. With Toyota's first move in the marketplace, four-wheelers could drive a 4WD mini right off the showroom floor.

In 1984, Toyota introduced the 4Runner sport utility vehicle. Several companies had been offering truck conversions with fiberglass camper shells, a walk-thru cab and fully upholstered custom interiors, but once Toyota delivered the factory models, these companies soon closed down.

There have been numerous body, chassis, driveline and engine changes since the first trucks arrived 20 years ago. Many of the specifications for the trucks also apply to the 4Runner, but variations between the two will be noted. Here, you'll see the differences between the various American models offered over the years.

NOTE: Click images for larger view.

Body:

There have been four different truck body styles over the years. From 1979 to 1983, Toyota offered a body with rounded fenderwells and round headlights, with the exception of the 1982 and 1983 models, which had rectangular headlights. From 1984 to 1988, the second-generation trucks had squarer fenderwells, and 1984 marked the year the Xtracab models were first introduced. Starting in 1989, Toyota returned to the rounded fenderwell, and the Xtracab length was stretched from 9 to 18 inches. The 1999.5 model was introduced as the new Tacoma truck and is still the current offering. Note that a double cab (four-door) model and some flatbed models are also available in countries outside the United States.

4Runner models for 1984 to 1989 followed the body style of the second-generation trucks. This was a two-door model, and the removable rear rooftop was made of fiberglass. Starting in 1999, the 4Runner had a full steel body, and the top could no longer be removed. 1990 also marked the year the four-door version was introduced. It would survive, but the last two-door models were shipped in 1992, the same year the flush headlights made their debut. In 1996, the larger third-generation body was introduced.

Wheelbase:

Front Suspension:

Toyota has used three different front driveline configurations over the years. From 1979 until 1985, a front live axle combined with semi-elliptic leaf springs was used. Front live axle models are still available in some body styles in countries outside the United States. Beginning in 1986, Toyota converted to an independent front suspension (IFS), utilizing upper torsion bars on both the truck and 4Runner. The first IFS models used 22.8mm torsion bars, but in 1988 they were reduced to 21.8mm to provide a slightly smoother ride.

The new Tacoma and the 1996 4Runner started the use of the coil spring/double wishbone suspension up front. This design increased front IFS suspension travel from about six inches to 7.7 inches. Power steering was an option for many years, starting with the first models in 1979. Currently, al1 4WD Tacoma trucks and newer 4Runners come factory-equipped with power-assisted rack-and-pinion steering.

Rear Suspension

All of the truck models have always had rear leaf springs. Beginning in 1989, the truck rear springs were increased in length to provide a smoother ride. The early 4Runners had a leaf spring rear suspension like the trucks. However, starting in 1990, the 4Runner cam equipped with a four-link coil rear suspension.

Engines:

Toyota has offered a number of four- and six-cylinder engines over the years. The table below lists these by model year.

Year / Model	I-4 (carb)	I-4 (EFI)	I-4 (turbo)	V-6 (EFI)
1979 - 1980	20R (2.2L)	N / A	N / A	N / A
1981 - 1984	22R (2.4L)
1985		22R-E (2.4L)
1986 - 1987			22R-TE	(2.4L) N / A
1988 - 1995	N / A		N / A	3VZ-E (3.0L)
1995.5 +		3RZ-FE (2.7L)		5VZ-FE (3.4L)

Some trucks were sold with a fuel-injected, turbo-charged 22R-TE engine option in 1986 and 1987. This was a move by Toyota to provide an engine with more power to compete with other manufacturers' V-6 engines until Toyota's became available. Many parts on the turbo trucks are stronger than on the standard engine truck. These include transmission and transfer case components, driveshafts, U-joints, differentials and axle gears. There were also a limited number of diesel 4WD trucks sold in the United States in the mid 1980s. Diesels are far more common in other countries.

Transmissions

The four-speed transmission was used in 1979 and 1980. The five-speed overdrive became available in 1981. Automatic transmissions have been available in all model-year trucks.

From 1979 through early 1981, Toyota 4WD trucks came with a four-speed transmission. These transmissions used a removable bellhousing and where often plagued with premature bearing wear problems. Late in 1981, the five-speed became available, which offered a 15-percent overdrive in fifth gear. From late 1981 through mid 1983, the five-speed transmissions used an integral bellhousing. Transmissions from these years, and also some 1984 models, suffered from bearing problems in the front cluster. These models can be retrofitted with larger bearings, or the transmission can be replaced with one of the later models.

Beginning in late 1983, the bellhousing could once again be removed from the transmission case, and the transmission became longer than that used in previous models. In the 1985 models, the transmission was fully changed to a much more durable design, which eliminated all of the bearing problems.

Transfer Cases:

Toyota has used three basic transfer cases over the years. A gear drive case was used in most four-cylinder models and a chain case in some automatic transmission four-cylinder and V-6 models, with the exception of the Tacoma. Early-model transfer cases have the front driveshaft output on the passenger side, but the Tacoma has the output on the driver side.

All high-range ratios in Toyota truck transfer cases are 1:1. All non-Tacoma four-cylinder trucks came with a 2.28:1 low range. Turbo four-cylinders, V-6s, and Tacomas all carry a 2.57:1 low range.

Over the years Toyota has offered both manual and automatic locking front hubs, depending on year and model. In 1986 models, the transfer case was changed so it could be shifted from 2-Hi to 4-Hi on the fly. In 1989, Toyota introduced the 4WDemand system on some models. This system allows the driver to shift from 4-Hi to 4-Lo while moving at 20 MPH or less. The Toyota ADD (Automatic Differential Disconnect) system is part of the 4WDemand system. In this system, there are no locking hubs, and the front axles and CV joints are constantly turning. A vacuum-actuated sliding sleeve assembly is mounted on the side of the differential to connect the left front drive axle to the differential.

Brakes

All Toyota truck rear axles come equipped with hydraulic drum brakes. Live axle trucks are equipped with 10-inch drums, and IFS trucks use larger 11.6-inch drums. The front disc brakes are power vacuum assisted. Live-axle models use 11.8-inch solid rotors, while the IFS models use 11.2-inch vented rotors.

As you can see, over the past 20 years of Toyota 4WD truck history, there have been a number of model changes and refinements. From leaf springs to torsion bars to coil springs, each equipment update has changed the character, handling and durability of the various models. Depending on your tastes and needs, you should be able to find the right model for you.

Axle Gear Ratios

The following table lists the gear ratios that were offered during the various model years.

Model Year	Gear Ratio(s)
1979	.10
1980	.38
1981	3.90
1982 - 1984	4.10
1985 - 1988	.10, 4.30, 3.42 (turbo trucks)
1985 - 1994	.10, 4.30, 4.56, 4.88 (not all gears for all years)
1995	3.91, 4.10
Tacoma	3.42, 3.91, 4.10

While this listing can be helpful, it is easy to check the ratio on the truck in question. This can be done by chalking a line on the driveshaft and one of the tires. Roll the truck so that the tire makes exactly one complete revolution and count the number of revolutions the driveshaft makes. This number will be the gear ratio.