Four-wheel drive tractors, as they used to say, were “slow a’bornin.'” Two-wheel drive was the norm until after World War II. Isolated attempts were made in the 1920s and ’30s, but steering difficulties (resulting from the fact that constant-velocity universal joints had not yet been invented) led to limited acceptance. More traction, in those days, came from tractors with crawler tracks.
Pivot steering, a type of articulation (or “bending in the middle”) was used on the 1915 Moline Universal, but with only two wheels driving. The back half had the seat and implement. It worked quite well, but it was a small, low-powered unit. Others of the time were two-wheel, front wheel drive, like the Universal, but used tail-wheel steering rather than the central-hinge articulation.
The real advantages of four-wheel drive became apparent in World War II, when front-wheel power could be engaged by the driver when needed. The terms “6×6” and “4×4” were coined, meaning all the wheels could be engaged, including the front (or steering) wheels.
The 1964 FWD/Wagner WA-4 was equipped with a GM/Detroit Diesel 4-53 engine that produced about 100hp.
Farming, construction, aviation and industry share common need
The first practical four-wheel drive farm “tractors” were post-war Willys Jeeps, Dodge Power Wagons and even the British Land Rover equipped at the factory with 3-point hitch and rear power take-off. While these rigs made important contributions to the idea of all-wheel drive, they really didn’t catch on with farmers, likely because of their limited maneuverability and visibility.
For years, farmers frustrated by the lack of higher-horsepower, better-traction tractors had been joining two tractors one behind the other (with the front wheels of both being removed) to make a single two-engine, four-wheel drive tractor. The driver sat on the rear seat controlling the rig via a hydraulic cylinder-powered articulation joint.
Providing clutch, shift and throttle control was the greatest challenge, but many one-of-a-kind machines of this type worked the fields. Ernest Doe & Sons produced quite a few Doe Dual Drive (also known as Triple D) tractors in the 1950s and ’60s. Built in Malden, Essex, England, the units were based on two Fordson Major tractors for a total horsepower of 107.
Also in the post-war era, four-wheel drives were offered with “skid-steering”; some had four-wheel steering. These met with limited acceptance. At that time, the industrial/construction industry was requiring bigger and more productive diggers and truck loaders. The aircraft industry, too, was coming out with airplanes with loaded weights of a half million pounds that needed to be moved around the factory and flight line.
The John Deere 8010 was John Deere’s first articulated four-wheel drive tractor.
The articulation advantage
The solution to these needs was big, heavy and powerful four-wheel drives. Manufacturers included Coleman, Euclid and Hough. Articulation was the solution to the needed maneuverability. Since weight and size were not a problem, the new-type articulated machines were just made beefy and strong. It wasn’t long before they were being considered for fieldwork.
The advantages of articulation included a tight turning circle, dual and triple tire installations, and even short tracks for flotation. A seldom recognized advantage is that the front and back wheels go in the same track, reducing soil compaction in turnarounds.
Problems with articulation stem mainly from transmitting power across the hinge joint. Some have solved this difficulty by using two engines, one for each axle. Kinze’s Big Blue, with two 320hp Detroit Diesels, is an example of that approach. Disadvantages include tying the controls together in the cab. Another example is the twin-engine Euclid scraper/earth-mover. The real pioneers of articulation in agriculture were two sets of brothers, the Steigers and the Wagners.
The Doe “Triple D” conversion of a Fordson Major first appeared in 1957. It was based on a British farmer’s invention designed to build a tractor with more power and traction. The Triple D was put into production by Ernest Doe & Sons in Malden, Essex, England.
Wagner’s roots in Pacific Northwest logging industry
Eddie Wagner and his six brothers were based in Portland, Oregon, where they worked in forestry, using mining and construction heavy equipment. Brother Elmer Wagner designed the first modern four-wheel drive articulated tractor in 1949 after returning from military service in Germany, and applied it to farm use in 1954. Full production of the TR-6, TR-9 and TR-14 began in late 1955.
A variety of power plants were used with little in the way of standardization until later. (It was said that no two Wagner tractors were alike in those days.) Wagner went through several ownership changes, including, for a time, a relationship with Clintonville, Wisconsin, fire truck builder FWD.
Eventually a deal was made with John Deere in December 1968 for exclusive rights to the WA-14 and WA-17 tractors. Although Deere took delivery of only 51 of these tractors (painted green and yellow), the deal included a clause that Wagner could not go back into production for at least five years, and that was the end of Wagner tractors.
The 1956 Model TR-9 used a 495-cubic-inch, 4-cylinder Cummins diesel that produced 125hp. It used a 10f/2r transmission and weighed in at about 16,000 pounds. It was tested by the Nebraska Tractor Test Lab as Test no. 631. The TR-14 was evaluated in Test no. 700 in 1959, with a Cummins diesel of 743 cubic inches. The model WA-4 with a 4-cylinder GM Detroit Diesel 2-cycle engine with 212-cubic-inch displacement was tested in Test no. 864 in 1964.
The International Harvester 2+2 design, introduced in 1979, was initially available in two models: the 130hp 3388 (pictured here) and the 150hp 3588.
Minnesota farmers launch Steiger line
Brothers Douglas and Maurice Steiger, Red Lake Falls, Minnesota, built their first articulated four-wheel drive tractor in their barn during the winter of 1957-58. The brothers reasoned that, if horsepower was equivalent to the rate of doing work, then they needed more of it to keep up with the requirements of their farm. They had available a GM Detroit Diesel 6-71 engine from a truck. The brothers reasoned that 238hp should be enough for their needs
The Steigers used the axles, radiator and pivot from a Euclid articulated scraper/hauler, but the Euclid used two engines (one for the front wheels and one for the back). The brothers had only one engine and had to come up with a way of getting the power across the pivot joint to the back wheels. Their solution was a center gearbox and four universal joints. The 2-speed, hand-made center gearbox (transfer case) was not fixed to either half of the tractor, but was allowed to translate left or right as the tractor “bent” for steering.
The swinging gearbox, as it came to be known, lessened the angles the universal joints had to make by a factor of four. Although universal angle was the limiting factor in steering angle on competitive (read: Wagner) designs, other manufacturers later copied the swinging box feature. Steiger went on to make more than 50,000 articulated tractors before being absorbed into CNH-Global.
The Steiger No. 1 of 1958 used a 10f-2r transmission/transfer case and weighed 18,000 pounds. It was not tested by the Nebraska Tractor Test Laboratory.
John Deere 8010/8020: big, powerful – and expensive
The massive John Deere 8010 startled Deere aficionados for more reasons than just its size when introduced in 1959. It was not only the first John Deere to exceed 100hp, it exceeded 200hp. Secondly, the model was the first Deere tractor with more than two cylinders since the ill-fated Dain all-wheel drive of 1919. Studies and experiments conducted by Deere in the years leading up to 1959 and the unveiling of the 8010 indicated that farmers would be interested in much more horsepower than was currently being offered. The studies also indicated that farmers would be ready and willing to pay for such power.
The Model 8010 and subsequent 8020 were big! The 8020 measured 20 feet long and 8 feet wide, and it was 8 feet tall. The 8020 used tires measuring 6 feet in diameter. The 6-cylinder GM Detroit Diesel 6-71 engine produced 215hp and had air brakes.
Two problems spelled trouble for the 8010. The first was that the 9-speed truck-type transmission could not stand the strain of tractor usage. The second was that while farmers would pay more for power, they were reluctant to pay that much more. In the early 1960s, Deere’s Model 4010 sold for less than $10,000, while the 8010 (by then rebuilt as the 8020) cost $30,000. In addition, implements absorbing that much horsepower were very expensive and not readily available.
Nevertheless, the 8010 was a remarkable tractor. After 100 Model 8010s were built and the transmission problems uncovered, most of them were recalled and rebuilt with an 8-speed, heavy-duty transmission and relabeled as 8020s. Because of the price, inventory languished well into 1964. Several escaped the rebuilding process; at least one was kept at the factory.
The GM Model 6-71 (Jimmy) diesel that powered the 8010/8020 was a 2-cycle engine. This type used a Roots-type blower to scavenge the exhaust and pressurize the inlet. In this application, it was rated at 2,100rpm, but being a 2-cycle engine with each cylinder having a power stroke on every revolution, it sounded like it was turning twice as fast as it actually was. It also had a steep torque curve and needed to be operated near top rpm. The result was startling for those accustomed to the pleasant exhaust note of the John Deere engine. Nicknamed “Howling Jimmy,” the Jimmy howled like a banshee at full-cry and could be heard miles away.
The 1959 John Deere Model 8010 had a 9f/1r transmission and weighed in at just under 20,000 pounds. It was not tested by the Nebraska Tractor Test Laboratory.
A 1971 White Plainsman A4T-1600. Photo by Andrew Morland
Minneapolis-Moline Plainsman A4T: competitive in a crowded field
The design of the A4T began in March 1969. Testing of prototypes began in May, with production starting in November. It was a remarkably short period of time for such a major change in configuration, but it resulted in an interesting story.
It seems an enterprising Minneapolis-Moline dealer in Stuttgart, Arkansas, had been building remarkably useful articulated four-wheel drive tractors from M-M components since 1962. When MM officials finally caught on, they copied the approach and made it into the Model A4T. By using existing axles, final drives, clutches, engines, radiators, controls, etc., much time and cost was saved.
The A4T was also quite price competitive, comparable to many two-wheel drive competitors. The engine chosen was the 504-cubic-inch M-M 6-cylinder unit available either as a diesel (139hp) or configured for LPG (169hp). A two-range, 5-speed transmission gave 10 speeds forward and two in reverse. A 1,000rpm PTO was provided.
By 1971, when the Plainsman A4T-1600 was submitted to the University of Nebraska for testing (no. 1071), a 143hp, 585-cubic-inch, 6-cylinder diesel was used. It weighed in at about 20,000 pounds. Virtually identical tractors were sold in the 1970s in Oliver and White livery.
International Model 6588/6788 doomed by corporate wrangling
International Harvester introduced a unique series of articulated four-wheel drive tractors called the 2+2 Series early in 1979. The nomenclature stood for “the convenience of a two-wheel drive tractor with the benefits of a fourwheel drive.”
The 2+2 was made up of the back half of a large IH two-wheel drive machine with the engine in front of the front axle, separated from the hinge joint by the fuel tank. This arrangement gave good weight distribution and made for a very quiet cab. Visibility of the work being done by towed implements was better than on other articulated machines.
Initially, the back portion was from an 86 Series tractor, but by the time Models 6588 (1982-84) and 6788 (1983-84) were built, the back half was from the 88 Series. These two versions were essentially the same in appearance. The 6588 had more transmission speeds, while the 6788 had more engine horsepower. The 6788 version had a 200hp turbocharged 6-cylinder diesel and weighed about 21,000 pounds.
The 2+2 Series was not tested at the Nebraska Tractor Test Laboratory.
The 2+2 tractors were quite successful from a user standpoint, and sold very well with well more than 3,000 sold. The devastating labor strike of 1979 set up the Ag portion of Harvester for acquisition by Tenneco in 1984. When Harvester was folded into Case to form Case-IH, the 2+2 Series was discontinued.
The articulated Plainsman was first produced by Minneapolis-Moline, but later sold as the Oliver 2655 and, later still, as part of the White line. The tractor’s engine was a 143hp MM 686-cubic-inch diesel. Photo from Mecum Auction.
Sales languish as farmers, manufacturers face unprecedented challenges
Times were tough in the tractor business in the 1970s, but that was nothing compared to the 1980s. Manufacturers had expanded their tractor lines and production facilities in the ’70s, and farmers had mortgaged and re-mortgaged land to buy equipment. Then interest rates began to climb. In 1980, the federal government initiated a grain embargo against the former Soviet Union.
The government also instituted the PIK (Payment-in-Kind) Program, which paid farmers to idle their land, but that, of course, further hurt implement manufacturers, already burdened with excess production capacity. Sales of four-wheel drive tractors, for example, declined 55 percent between 1979 and 1983.
By 1988, the picture began to brighten. Sales of articulated tractors increased for the first time in the decade.
New models featured improved operator convenience, comfort and soundproofing. Electronic displays monitored everything from wheel slip to the rate of pesticide application. One version included automatic traction control. Steiger pioneered the use of the 5-speed Allison automatic transmission with torque converter. Then, power shift transmissions became the norm. John Deere introduced its first diesel V-8, while Big Bud went to a V-12 on its Model 500.
The very large tractor market reached a horsepower peak in the late 1970s. During the ’80s, average power of the articulated tractor settled down to about 300 engine horsepower. Mechanical front-wheel drive conventional tractors gained popularity with horsepower between 150 and 200 for the largest units. FC
After 36 years in the aircraft industry, Bob Pripps returned to his first love and began writing about tractors. He has authored some 30 books on the subject and several magazine articles. Pripps has a maple syrup farm near Park Falls, Wisconsin. In harvesting the maple sap, he relies on a Ford Jubilee and a Massey Ferguson 85.