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IHC's row-crop revolution

Once maligned, misunderstood, and often made light of, history is coming to judge International Harvester’s unique 2+2 tractors in more favorable terms, as collectors increasingly vie for them at auction.

More a victim of corporate mismanagement and tough economic times, the 2+2 was, in fact, a huge success story for the beleaguered International Harvester Company. For in its first year of production, nearly 3,000 of the models 3388 and 3588 sold.

Capture 1/4 of the market

This represented over one quarter of four- wheel-drive (4WD) sales in 1979 – an accomplishment unheard of before or after this time for an entirely unique design introduction.

“Here is the versatility and maneuverability of a two-wheel drive…plus the traction, stability, and flotation of two more drive wheels,” IHC promotions boasted at the time the 2+2s were introduced.

Unlike conventional 4WD tractors, the 2+2s had their cabs located behind the articulation joint. This rear portion of the tractor was actually the rear half of the existing 86 series two-wheel-drive IHCs. Furthermore, the power plants on the 2+2s were mounted ahead of the front axle, similar to the 66 and 86 series Internationals. Locating the engine there increased the weight on the front drive axle to improve traction.

Efficient to build

The 2+2s’ unique design aside, these tractors were also conventional, as they readily utilized major components in use by other IHC tractors. Employing existing rear drives and front power trains allowed the 2+2s to be designed with very few drive train modifications.

IHC’s use of existing technology didn’t end there. The tractors employed existing IHC-built engines. The model 3388 ran with the model DT-436 turbo- charged engine rated for 130 PTO hp. The model 3588 was propelled by the model DT- 466 turbocharged unit rated at 150 PTO hp.

This approach of employing existing components in their manufacture continued as new 2+2 models were introduced by IHC at almost a frantic pace.

Rapid succession of 2+2s

The 3388 and 3588 were introduced in 1978 and were produced from 1979 to 1981. In 1980, a third 2+2 model, the 170-hp. 3788, was introduced. Just two years later, a new series of tractors was trotted out in the mod- els 6388 and 6588. They remained in production from 1982 to 1984. In 1983, the model 6788 replaced the 3788.

Finally, 1984 saw the introduction of the Super 70 series 2+2 in the form of the 7288 and 7488. A model 7788 was in development to replace the 6788, but it never saw production. Replacements for the 7288 and 7488 were on the drawing board in the never-built models 7688 and 7888.

Popular design

This rapid replacement of models was not, as some tractor historians have contended, a way for IHC to compensate for design flaws in the 2+2s. Rather, the tactic was a means to capitalize on the tractor’s popularity. This crossover tractor offered row-crop farmers the best of both worlds: a 4WD that could readily negotiate rows due to a 15.9-foot turning radius.

The 2+2s were feature-rich. For example, the engine compartment of the tractors was completely enclosed to keep the engine cleaner and to reduce engine noise. The cab on the 3388 was tested, producing 78.5 decibels. This compared to 81 decibels in the IHC model 4788.


Another advance included a Category III three-point hitch that offered draft control utilizing IHC’s
exclusive torsion-bar low-link sensing system. This feature automatically adjusted three-point height when a mounted implement hit a tough spot in the field.

Hydraulic power for the three-point hitch and hydraulic outlets was supplied by an industry-exclusive pressure and flow- compensation system. This design sensed the amount of hydraulic power needed and then automatically delivered only that power, thereby, not sapping energy away from the engine.

State-of-the-art tranny

The 2+2 line employed IHC’s torque amplifier eight-gear transmission with two ranges and partial powershifting on- the-go and under load within its 16 operating speeds. This tranny was first introduced by IHC in 1972 and employed an improved version of its Torque-Amplifier feature.

Later 2+2s would work with an improved transmission tabbed the Synchro Tri-Six or STS. This design had six gears in each of three ranges offering 18 forward speeds. As before, the transmission provided the ability to partially powershift between gears within a range. For all its features and unique design, the 2+2 could not overcome a juggernaut of problems assaulting IHC at the time of its production.

Victim of the times

The company, once number one in farm equipment sales in the U.S., had slipped to number two behind John Deere. Burdened by an abundance of aging factories, mounting employee benefit costs, and management missteps, IHC was suffering from a financial meltdown while the 2+2 was enjoying success.

A devastating labor union strike in 1979 cost the company $579 mil- lion in losses. This was exacerbated by the fact that IHC had an enormous inventory of machinery on hand prior to the strike that had to be sold in an economy that was less than rosy. Four-wheel-drive sales, for example, plummeted 55% from 1979 to 1983. Management seemed oblivious to this fact. Instead, it put the spurs to production, turning out more machinery and growing inventory.

On November 26, 1984, Tenneco bought out IHC’s ag division, merging it with its machinery firm, Case. In the ensuing months, management of the new company, tabbed Case IH, opted to kill all IHC tractor models above 80 hp. This eliminated the 2+2 line, and the design was shelved forever.

In its place, Case IH would develop the Magnum line, which featured front-wheel drive. This advance, first introduced by Minneapolis-Moline in 1962, was coming to its own with farmers still yearning for a four- wheel-powered tractor with the agility to run down rows.

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