International Harvester 656: Evolution of a Farm Workhorse with Hydrostatic Innovation

Most farms have a utility tractor around. It usually mounts a hydraulic loader but may also be used with other powered implements. The utility will perform a lot of different jobs around the farm and it gets the tractor equivalent of stop-and-go commuter miles. As a farmer upgrades his equipment, yesterday’s main tractor often becomes today’s utility tractor, so “ye olde utility” may have a long life on a farm.

By the early 1960s International desperately needed new tractors to overcome the lead John Deere had gained on them in the late 1950s. Knowing a big chunk of that gain was International’s own fault didn’t help. The debacle of the 560’s final drive failures haunted the company like a persistent poltergeist. Well, International got it right with the 706 and 806, and soon a smaller 606 and a larger 1206 joined the ranks. While these tractors didn’t move them past the “Big Green Machine,” at least they put them within spitting distance.

In 1966, the 606 received a number of upgrades and became the first of the 56 series tractors, the 656. The 756 and 856 followed shortly but that isn’t the big story. The 656 became the point tractor for a big innovation in tractor technology, the hydrostatic drive. IH had been working on a hydrostatic drive since the early 1960s and used one in their innovative HT-340 gas-turbine tractor. IH had big plans and the 656 would be the first production tractor to bring hydrostatic drive to the farm.

Hydrostatic drive, trade named Hydro by IH, didn’t quite make the intro of the 656 line, but had its own debut in the summer of 1967. So what’s hydrostatic drive? You could say it’s an early CVT (Continuously Variable Transmission). You could also say it’s a form of power shift. In reality it’s a hydraulic drive system where the engine drives a huge pump on one side and a huge hydraulic motor is connected to the final drive. In between is a control that varies the volume and pressure going from the pump to the motor. This is a vastly simplified description, of course.

On the upside, the Hydro had infinitely variable speed control which was very useful for many farm tasks where a lot of forwards and back operation is needed. On the downside, there’s some power loss and it was possible to overheat the transmission oil in heavy use. They also weren’t simple to service or repair for owners and techs used to gears.

The Hydro 656 was well received, as were the other Hydros that followed—the 544, 826 and the first 100+ hp hydrostatic tractor, the 1206. Depending on whom you ask, you will hear tales of woe or tales of joy regarding the IH Hydros when some old farmer bends your ear. The truth is somewhere near the middle. A well-maintained Hydro used within its capabilities could last as long as any other tractor. When used beyond the limits, or neglected, they could fail rather spectacularly. Most will agree they had somewhat more no-fault-of-the-operator failures than the average gear-drive tractors but they certainly weren’t a disaster. On the right farm, they were a Godsend and worth a little extra trouble.

There was more to the 656 than the Hydro. They also came with a five-speed mechanical trans with a torque amplifier. You could order them with either a 262-cid gas six (64 PTO hp) or a 282-cid diesel. By the late 1960s, gas tractors were on the way out and most 656s are found with the D282 diesel. It could be ordered with a wide or narrow front axle. Most came with a three-point hitch, PTO and drawbar but a belt pulley drive was still on the options list.

The D282 six-cylinder had debuted with the 560 line in 1958 and was a reworked gasser. It was a four-main, naturally aspirated, dry-sleeved, indirect-injected powerplant with not quite enough head bolts, but by the time the 656 came along, the bugs were worked out and the engine had gained some power along the way. A big-bore, unsleeved 301-cid version (D301) was produced and used in trucks and combines.

The 656 was produced through 1972 and superseded by the upgraded 666 (the Devil’s tractor… muahahahaha!). The 666 was similar in concept but used the D312 diesel, which was a relative of the legendary D360 engine. For 1973, the hydrostatic versions of the 666 were renamed the Hydro 70.

The 656, Hydro or gear drive, was a popular tractor and a bit more that 8,200 were built into 1973. Like John Hoshock’s 1970 Hydro shown here, many are still at work. There isn’t a better testament to quality than that! DW

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FREQUENTLY ASKED QUESTIONS

How did the hydraulic system of the Farmall 656 work, and what capacities did it offer?

The hydraulic system of the Farmall 656 was designed for efficiency and versatility, boasting ample capacity for a range of agricultural tasks. Here’s a breakdown of how it functioned and the capacities it offered:

Primary Hydraulic System

• Flow Rate: The main hydraulic system had a total flow rate of 12 gallons per minute (gpm).
• Power Steering: Out of this, 3.5 gpm was specifically allocated to operate the hydrostatic power steering, ensuring smooth and effortless steering control.

Transmission and Remotes

• Lubrication and Power: The remainder of the primary system’s capacity, 8.5 gpm, was used to lubricate the transmission and provide hydraulic power to the remote outlets, enhancing the tractor’s operational flexibility.

Secondary Hydraulic Features

• Hitch System: A separate hydraulic pump provided an additional 7.5 gpm dedicated to the tractor’s hitch. This system could also work in tandem with the primary system, offering enhanced capacity when the hitch was inactive.

Optional Power-Shift PTO

• Additional System: For tractors equipped with the power-shift power takeoff (PTO), an extra 3 gpm system was included. This system specifically powered the hydraulic clutch for the PTO, completing the tractor’s robust hydraulic capabilities.

In summary, the Farmall 656’s hydraulic system was a well-orchestrated blend of multiple systems, each playing a critical role in the machine’s performance and versatility in the field.

 

Why was the 656 chosen as the platform to introduce the hydrostatic transmission?

The decision to introduce the hydrostatic transmission on the 656 model was strategic and rooted in popularity and functionality. In the year it succeeded the 606, the 656 maintained much of its predecessor’s design, ensuring familiarity for users. However, the standout feature was its novel transmission system, a significant innovation.

According to a June 1967 issue of Machine Design magazine, the company selected the 656 model because it was their most popular tractor at the time. This widespread acceptance made it an ideal candidate to showcase new technology. By offering both utility and row-crop versions equipped with the innovative hydrostatic transmission, the company could effectively demonstrate the enhanced ease of use and efficiency unique to this system while appealing to a broad base of existing and potential customers.

 

What safety features were included in the 656 Hydro’s design?

Safety Features in the 656 Hydro’s Design

The 656 Hydro was equipped with several innovative safety features to enhance operator control and comfort. Here’s a breakdown:

• Neutral Position Design: The speed ratio selector in the 656 Hydro featured a uniquely designed guide slot. This slot included a horizontal step at the neutral position, effectively preventing the operator from accidentally overshooting it when shifting between forward and reverse.
• Inching Pedal for Panic Stops: Despite being clutchless, the tractor included an inching pedal specifically for emergency stops and to boost operator confidence. Activating this pedal released the hydraulic pressure from the transmission pump, bringing the tractor to a swift halt.
• Gradual Clutch Simulation: To prevent abrupt starts, especially when the speed-ratio lever was set to extreme positions, the design incorporated a system that gradually pressurized the pump. This mimicked the smooth engagement of a mechanical clutch, allowing for precise and controlled movements, particularly useful for delicate operations like attaching equipment or performing precision loader work.

These features were not only safety measures but also contributed to the tractor’s ease-of-use, ensuring more controlled operations in varied agricultural tasks.

 

What was the function of the Torque Amplifier in the Farmall 656?

The Torque Amplifier in the Farmall 656 served a vital role in enhancing the tractor’s versatility and performance. It effectively expanded the transmission options, allowing the operator to access a total of ten gears. This feature provided a high and low range for each gear, enabling seamless shifting on the go. The result was improved adaptability across various farming tasks, from plowing fields to navigating challenging terrains, offering both power and control when needed.

 

What were the capabilities and features of the 656 Hydro’s engines and transmission?

The D282 had more than a decade in service by the time this one was built for 1970 and it would go on for almost another decade. It was indirect injected, direct start and used a Roosa Master DB pump with IH Midget injectors. In later years, they were commonly rated at about 70 PTO hp, but the later engines held up pretty well at 90 hp if aftermarket turbocharged.

Engine Options and Performance

As with the gear-drive 656 tractors, the 656 Hydro models were available with the C-263-cubic-inch gasoline or D-282-cubic-inch diesel engines. The engines were governed at 2,300 rpm rather than 1,800, providing about 66 horsepower at the power takeoff and 52 horsepower at the drawbar in both diesel and gas versions.

Hydrostatic Drive and Transmission

Hydrostatic drive, trade named Hydro by IH, didn’t quite make the intro of the 656 line, but had its own debut in the summer of 1967. This drive system was an early form of CVT (Continuously Variable Transmission) and could also be seen as a type of power shift. Essentially, it’s a hydraulic drive where the engine powers a large pump on one side and a large hydraulic motor is connected to the final drive. Between them is a control that adjusts the volume and pressure passing from the pump to the motor. This setup allowed for infinitely variable speed control, which was incredibly useful for tasks requiring frequent changes in direction.

Power from the engine was transmitted to the ground through the hydrostatic transmission via a two-speed Hi Lo gearbox to a conventional differential and bull-gear final drive. In high range, forward and reverse speeds of 0–20 and 0–9 miles per hour were achievable, while in low range, speeds of 0–8 mph (forward) and 0–4 mph (reverse) were possible.

Additional Features and Considerations

On the upside, the Hydro had infinitely variable speed control which was very useful for many farm tasks where a lot of forwards and back operation is needed. On the downside, there’s some power loss and it was possible to overheat the transmission oil in heavy use. They also weren’t simple to service or repair for owners and techs used to gears.

There was more to the 656 than the Hydro. They also came with a five-speed mechanical trans with a torque amplifier. You could order them with either a 262-cid gas six (64 PTO hp) or a 282-cid diesel. By the late 1960s, gas tractors were on the way out and most 656s are found with the D282 diesel. It could be ordered with a wide or narrow front axle. Most came with a three-point hitch, PTO and drawbar but a belt pulley drive was still on the options list.

The rear view with a big IH snow blower. It’s probably accurate to say the 656 Hydro saw the most service as a utility tractor but that didn’t mean it couldn’t also be a tillage workhorse. They were actually quite nice hooked up to a plow because of the superior control and lack of need to shift. It was often said that long-term transmission durability could be an issue for tractors often used for heavy tillage but the biggest issue was an increase in fuel consumption versus a gear tractor.

 

What were the specific speed capabilities of the 656 Hydro in forward and reverse?

In high range, forward speeds reached up to 20 mph with reverse going up to 9 mph. In low range, forward speeds were limited to 8 mph and reverse to 4 mph.

 

How was power transmitted from the engine to the ground in the 656 Hydro?

Power was channeled through a hydrostatic transmission using a two-speed Hi Lo gearbox, leading to a conventional differential and bull-gear final drive.

 

What were the specific horsepower ratings for the 656 Hydro models at the power takeoff and drawbar?

These models delivered about 66 horsepower at the power takeoff and 52 horsepower at the drawbar.

 

What was the governed engine speed for the 656 Hydro engines?

The engines were set to run at a maximum of 2,300 revolutions per minute.

 

What engine options were available for the 656 Hydro models?

The 656 Hydro models came with either a gasoline engine of 263 cubic inches or a diesel engine of 282 cubic inches.

 

What model replaced the 656, and what improvements did it include?

The 656 was produced through 1972 and superseded by the upgraded 666 (the Devil’s tractor… muahahahaha!). This new beast on the block debuted with a pair of fresh engines, enhancing its power and efficiency. The 666 was similar in concept but used the D312 diesel, which was a relative of the legendary D360 engine. Alongside the new engines, several other improvements were introduced, making the 666 a robust successor with enhanced features ready to tackle the toughest of tasks.

Whether you’re drawn to the mystique of its name or the muscle under its hood, the 666 stood out as a formidable upgrade from its predecessor.

 

Were there other improvements besides the engine?

Yes, the Model 666 featured several other enhancements beyond just the new engines.

 

What engines were introduced with the new model?

The Model 666 was launched with two new engine options.

 

What was unique about the hydrostatic transmission in the 656 Hydro compared to others?

**Hydrostatic drive, trade named Hydro by IH, didn’t quite make the intro of the 656 line, but had its own debut in the summer of 1967. So what’s hydrostatic drive? You could say it’s an early CVT (Continuously Variable Transmission). You could also say it’s a form of power shift. In reality, it’s a hydraulic drive system where the engine drives a huge pump on one side and a huge hydraulic motor is connected to the final drive. In between is a control that varies the volume and pressure going from the pump to the motor. This is a vastly simplified description, of course.

The 656 Hydro’s transmission was a product of over a decade’s worth of innovation, drawing inspiration from heavy-duty torque converters and fluid-drive systems from the automotive world. Engineers experimented with hydraulic pumps connected to individual wheel motors, aiming to perfect a design that balanced performance with reliability.

On the upside, the Hydro had infinitely variable speed control, which was very useful for many farm tasks where a lot of forwards and back operation is needed. It offered a design reminiscent of the hydrostatic transmission found in successful lines, but with a key distinction: both the hydraulic pump and motor featured variable-displacement cylinders. This allowed for greater flexibility and control.

On the downside, there’s some power loss, and it was possible to overheat the transmission oil in heavy use. They also weren’t simple to service or repair for owners and techs used to gears. Despite these challenges, the unique engineering of the 656 Hydro set it apart, making it a notable advancement in the field of agricultural machinery.

 

What specific technical features make the 656 Hydro’s transmission unique?

A distinctive feature of the 656 Hydro’s transmission is that it includes both a hydraulic pump and motor with variable-displacement cylinders, setting it apart from other similar systems.

 

How does the 656 Hydro’s transmission compare to other existing transmissions?

The design of the 656 Hydro’s transmission is similar to the hydrostatic transmission from the Sundstrand Corporation, which was used in the popular Cub Cadet line. However, it differs in some technical aspects, offering unique features.

 

What was the development history of the 656 Hydro’s transmission?

The 656 Hydro’s transmission was developed over more than ten years, incorporating elements from heavy-duty torque converters and fluid-drive systems used in the automotive sector, as well as hydraulic systems linked to individual wheel motors.

 

What were the principal variants of the Farmall 656, and what features did they have?

The Hydro 656 was well received, as were the other Hydros that followed—the 544, 826 and the first 100+ hp hydrostatic tractor, the 1206. Depending on whom you ask, you will hear tales of woe or tales of joy regarding the IH Hydros when some old farmer bends your ear. The truth is somewhere near the middle. A well-maintained Hydro used within its capabilities could last as long as any other tractor. When used beyond the limits, or neglected, they could fail rather spectacularly. Most will agree they had somewhat more no-fault-of-the-operator failures than the average gear-drive tractors but they certainly weren’t a disaster. On the right farm, they were a Godsend and worth a little extra trouble.

There was more to the 656 than the Hydro. They also came with a five-speed mechanical trans with a torque amplifier. You could order them with either a 262-cid gas six (64 PTO hp) or a 282-cid diesel. By the late 1960s, gas tractors were on the way out and most 656s are found with the D282 diesel. It could be ordered with a wide or narrow front axle. Most came with a three-point hitch, PTO and drawbar but a belt pulley drive was still on the options list.

While the Hydro 656 shone on many farms, the Farmall 656 lineup offered more than just hydrostatic innovation. Among the principal variants were the High-Clear and the Western Special. The High-Clear variant was engineered for exceptional ground clearance, providing 37 inches under the rear axles and 34 inches at the front—an impressive leap from the standard 15 and 21 inches. This feature made it particularly valuable for operations requiring higher clearance.

Meanwhile, the Western Special, a unique Wheat Land variant, was built on the Farmall chassis. This model featured a more enclosed operator’s station and included shockproof lights and a PTO with a power shift hydraulic clutch. It even offered an optional cab for added comfort. Unlike most standards, it maintained adjustable axles and the typical Farmall ground clearance, setting it apart from the rest.

By 1966, the International utility version of the 656 was available in both standard and High-Clear variations, broadening its appeal. Notably, by the end of that year, nearly 16,000 units had been built, marking a significant milestone in the Farmall legacy.

 

When was the International utility version of the 656 introduced?

The International utility version of the 656 was introduced by 1966, available in both standard and High-Clear variations.

 

What was the production timeline and volume for the 656 tractors?

By the end of 1966, nearly 16,000 units of the 656 tractors had been produced.

 

How does the Western Special differ from standard models?

Unlike standard models, the Western Special is a Wheat Land variant with adjustable axles and a more enclosed operator’s station.

 

What are the specific features of each variant?

The High-Clear model features increased clearance under the axles, while the Western Special includes an enclosed operator’s station, shockproof lights, and optional cab, among other features.

 

What are the principal variants of the Farmall 656?

The principal variants of the Farmall 656 include the High-Clear and the Western Special models.

 

How was power transmitted from the engine to the wheels in the Farmall 656?

“In reality, it’s a hydraulic drive system where the engine drives a huge pump on one side and a huge hydraulic motor is connected to the final drive. In between is a control that varies the volume and pressure going from the pump to the motor.” This innovative hydraulic setup works in tandem with a traditional mechanical system to efficiently transmit power to the rear wheels.

The power from either engine is initially transmitted through a robust 12-inch Dyna-Life single-dry-disc clutch. This component is crucial for managing the engagement between the engine and the drivetrain. The system then feeds into a five-speed sliding-spur-gear agricultural transmission, ensuring smooth and reliable power delivery.

Further enhancing the transmission is the gear reduction at the differential, paired with bull-gear type final drives. These components work together to manage and optimize the power flow to the wheels, providing the necessary torque and handling for various tasks.

For those seeking even greater versatility, an optional Torque Amplifier is available. This feature effectively doubles the number of available gears to ten, allowing for high/low shift on the fly for each gear. It significantly enhances the tractor’s adaptability to different working conditions.

Moreover, tractors without the Torque Amplifier option can be equipped with a forward-reverse attachment. This attachment provides five forward gears and five reverse speeds, which are slightly higher than their forward counterparts. This innovative feature simplifies repetitive forward-reverse operations, making tasks like loader work more efficient and less cumbersome.

By combining advanced hydraulic technology with mechanical precision, this system exemplifies a seamless integration of power and control, tailored to meet the demands of modern agricultural tasks.

 

How does the optional forward-reverse feature work?

This feature offers five forward gears paired with slightly higher five reverse speeds, enhancing efficiency in repetitive tasks.

 

What optional features affect power transmission?

Optional features include a Torque Amplifier that increases available gears to ten and a forward-reverse attachment providing additional gear versatility.

 

What type of final drives are used?

The tractor is equipped with bull-gear type final drives, crucial for delivering power to the wheels.

 

How is gear reduction achieved?

Gear reduction occurs at the differential, adjusting engine power for optimal wheel performance.

 

What type of transmission is employed?

It features a five-speed agricultural transmission utilizing sliding-spur gears.

 

What type of clutch is used?

The tractor uses a 12-inch single-dry-disc clutch designed for effective power transmission.

 

What series did the International 656 tractor replace, and when was it introduced?

In 1966, the 606 received a number of upgrades and became the first of the 56 series tractors, the 656. The 56 series was introduced specifically to replace the older 06 series, marking a significant evolution in tractor design and functionality. The transition began with the launch of the 656 model in 1965, setting a new standard in agricultural machinery with its innovative features and improved performance.

This introduction not only signaled the end of the 06 series but also ushered in a new era for farmers seeking enhanced efficiency and reliability. By refining and updating the existing 606 model, the 656 embodied the technological advancements that characterized the 56 series, offering greater power and versatility for a variety of farming needs.

 

What was the first model of the 56 series?

The initial model of the 56 series was the 656.

 

When was the 56 series introduced?

The 56 series made its debut in 1965.

 

What series did the International 656 tractor replace?

The 656 was part of the 56 series, which was intended to replace the 06 series.

 

Why was the 656 chosen as the platform to introduce a hydrostatic transmission?

The decision to use the 656 as the platform for launching a hydrostatic transmission was largely strategic. The 656 replaced its predecessor, the 606, with minimal changes but included a crucial upgrade: the addition of new utility and row-crop versions equipped with an innovative hydrostatic transmission designed by the company.

This choice was influenced by the tractor’s popularity. As it was one of the most widely used models, introducing cutting-edge technology on a familiar platform ensured a smooth transition and higher acceptance among users. The decision was highlighted in a Machine Design magazine article from June 8, 1967, emphasizing that the tractor’s extensive user base and reliability made it the ideal candidate to debut this technology.

By leveraging the existing trust and familiarity farmers had with the 656, the brand aimed to encourage adoption of the new transmission system, reducing risks and uncertainty for both the company and its customers.

 

What were the engine specifications for the 656 Hydro?

Engine Specifications for the 656 Hydro

The 656 Hydro tractor offered two engine options. Buyers could choose between a C-263 cubic inch gasoline engine or a D-282 cubic inch diesel engine. These engines were designed to run at higher speeds, with a governing rate of 2,300 rpm, as opposed to the 1,800 rpm commonly found in other models. This increased rpm allowed the engines to deliver approximately 66 horsepower at the power takeoff and 52 horsepower at the drawbar in both the gasoline and diesel versions.

Transmission and Speed Capabilities

Power from the engine was efficiently delivered to the ground through a hydrostatic transmission. This was paired with a two-speed Hi Lo gearbox, leading to a conventional differential and bull-gear final drive. The hydrostatic transmission allowed for variable speed settings:

• High Range:
  • Forward speeds of 0–20 mph
  • Reverse speeds of 0–9 mph
• Low Range:
  • Forward speeds of 0–8 mph
  • Reverse speeds of 0–4 mph

 

How did the shuttle-like innovation benefit the operation of the Farmall 656?

The shuttle-like innovation significantly enhanced the efficiency and ease of operating the Farmall 656, particularly during tasks that involved constant directional changes. By streamlining forward-reverse maneuvers, it allowed operators to perform loader work with greater speed and comfort. This advancement reduced the amount of manual input required, decreasing operator fatigue and increasing productivity. Handling tasks that demanded frequent switching from forward to reverse became much smoother and less time-consuming, enabling workers to complete projects more effectively.

 

How did the hydrostatic transmission of the 656 differ from the Sundstrand Corporation’s design?

The hydrostatic transmission of the 656 set itself apart through an innovative design that involved years of rigorous experimentation. While it drew inspiration from the automotive industry’s use of torque converters and fluid-drive systems, its final form had unique elements.

A critical difference lay in the transmission’s components: both the hydraulic pump and motor were equipped with variable-displacement cylinders. This diverged from the design by Sundstrand Corporation, which was known for its fixed-displacement approach in their widely adopted hydrostatic transmissions.

This variability enabled the 656 to offer more precise control and adaptability, marking a significant evolution in transmission technology.

 

What was the hydraulic capacity of the Farmall 656, and what systems did it power?

The Farmall 656 boasted impressive hydraulic capabilities, featuring a main hydraulic system with a capacity of 12 gallons per minute (gpm). Of this, 3.5 gpm was dedicated to its fully hydrostatic power-steering system, ensuring smooth maneuverability. The remaining 8.5 gpm served dual purposes: lubricating the transmission and powering the remotes.

Additionally, a distinct 7.5-gpm pump powered the tractor’s hitch. This system could also supplement the primary hydraulic functions when the hitch wasn’t engaged. For models equipped with an optional power-shift power takeoff (PTO), a separate 3-gpm system was tasked with operating the PTO’s hydraulic clutch. Together, these features made the 656 an adaptable and versatile farming machine.

 

What optional feature doubled the number of available gears in the Farmall 656?

The Farmall 656 offered an optional feature known as the Torque Amplifier. This feature effectively expanded the number of gears from five to ten by allowing high/low shifting in each gear while the tractor was in motion.

 

What safety feature was incorporated into the 656 Hydro’s clutchless design?

The 656 Hydro integrated a crucial safety feature to prevent sudden, unintended movements when operating the machine without a traditional clutch. Engineers crafted a system that gradually applied pressure to the hydraulic pump as the operator released the clutch pedal. This mechanism mimicked the smooth engagement of a traditional clutch through its friction point. Originally designed as a safety measure, this feature not only enhanced control but also offered convenience for tasks requiring precision, such as slowly moving attachments into place or conducting precise loader operations.

 

What were the principal variants of the Farmall 656 during its first year of production?

The initial production year of the Farmall 656 introduced two main variants: the High-Clear and the Western Special.

• High-Clear Variant: This model offered significantly increased ground clearance with 37 inches under the rear axle and 34 inches under the front, compared to the standard 15 and 21 inches. This higher clearance made it particularly suitable for specific agricultural tasks requiring more vertical space.
• Western Special Variant: This wasn’t a standard version but was tailored for wheat farming, based on the Farmall chassis. It featured a more enclosed operator’s station for added comfort, shockproof lighting, a PTO with a power shift hydraulic clutch, and the option of an enclosed cab. Notably, it maintained adjustable axles and the Farmall’s typical ground clearance.

By 1966, an International utility version of the 656 was also available in both standard and High-Clear variations. By year’s end, nearly 16,000 units were produced, marking a successful launch for these versatile machines.

 

What changes were made to the Farmall 656 in 1967?

In 1967, the Farmall 656 underwent several notable updates. Most visibly, the tractor received a refreshed appearance, including a redesigned grille. The older white mesh grille was replaced with a modern tubular steel version. Additionally, both the utility and row-crop models now sported the label “International” on their side panels. However, on the row-crop version, “Farmall” appeared beneath the number on the badge located on the grille housing.

A significant technical advancement for the Farmall 656 was the introduction of an innovative hydrostatic transmission. This new transmission was featured in both utility and row-crop models. The decision to introduce this advanced technology on the 656 stemmed from its popularity within the company’s lineup.

The hydrostatic transmission was a culmination of extensive research and development, drawing from over a decade of experimentation. The company had explored various technologies, such as torque converters and fluid-drive transmissions borrowed from the automotive sector, as well as hydraulic pumps linked to individual wheel motors. The final design closely resembled a successful model by Sundstrand Corporation, though with distinct enhancements including variable-displacement cylinders in both the pump and motor aspects of the 656’s transmission system.

 

What was a downside to the 656 Hydro models compared to their gear-driven counterparts?

On the downside, there’s some power loss and it was possible to overheat the transmission oil in heavy use. They also weren’t simple to service or repair for owners and techs used to gears. Additionally, the 656 Hydro models had another significant drawback: they were not as fuel-efficient as their gear-driven siblings. This meant that while they offered smoother operation, they could end up costing more in fuel over time, a factor worth considering for those looking to maximize efficiency and minimize operating costs.

These aspects present a stark contrast to the more straightforward gear-driven models, which provide ease of maintenance and better fuel economy. For users prioritizing long-term cost-effectiveness and simplicity, these differences are crucial.

 

How does the fuel efficiency of the 656 Hydro models compare to their gear-driven counterparts?

The 656 Hydro models are less fuel-efficient than their gear-driven counterparts.

 

How was power transmitted from the engine to the rear wheels in the Farmall 656?

Hydrostatic drive, trade named Hydro by IH, didn’t quite make the intro of the 656 line, but had its own debut in the summer of 1967. So what’s hydrostatic drive? You could say it’s an early CVT (Continuously Variable Transmission). You could also say it’s a form of power shift. In reality it’s a hydraulic drive system where the engine drives a huge pump on one side and a huge hydraulic motor is connected to the final drive. In between is a control that varies the volume and pressure going from the pump to the motor. This is a vastly simplified description, of course.

To truly understand the power transmission in the Farmall 656, let’s dive into the original setup. Power from the engine was channeled to the rear wheels through a robust 12-inch Dyna-Life single-dry-disc clutch. This clutch connected to a five-speed sliding-spur-gear agricultural transmission, ensuring reliable power transfer.

The system also included gear reduction at the differential and bull-gear type final drives, providing the necessary torque and control for various tasks. For those seeking enhanced performance, an optional Torque Amplifier was available. This ingenious addition doubled the number of gears to ten, offering a high/low shift on the fly for each gear.

For operators focused on efficiency, tractors without the Torque Amplifier option could be equipped with a forward-reverse attachment. This feature provided five forward gears alongside five reverse speeds, slightly higher than their forward counterparts. Such versatility made loader work and other repetitive operations smooth and efficient.

This combination of traditional and innovative transmission solutions illustrates the versatility and adaptability of the Farmall 656, catering to varied agricultural needs.

 

How did these features improve functionality?

These features simplified tasks like loader work and repetitive forward-reverse operations, making the tractor more efficient in such scenarios.

 

Were there any optional features for enhancing transmission?

Yes, there was an optional Torque Amplifier that increased the number of gears to ten and a forward-reverse attachment for greater versatility.

 

How was gear reduction achieved?

Gear reduction was accomplished through mechanisms at the differential and bull-gear type final drives, optimizing power delivery.

 

What type of transmission system was implemented?

It featured a five-speed sliding-spur-gear transmission, commonly used in agricultural machinery for robust performance.

 

What type of clutch was used?

The Farmall 656 was equipped with a 12-inch single-dry-disc clutch, designed for efficient power transmission to the rear wheels.

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