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

FREQUENTLY ASKED QUESTIONS

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 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 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.

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.

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.

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 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 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.

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.

What engine specifications are included in the International Harvester 656 Tractor Engine Parts Manual (Engine)?

Engine Specifications in the International Harvester 656 Tractor Engine Parts Manual

The International Harvester 656 Tractor Engine Parts Manual encompasses comprehensive details on several key engine specifications. Here’s a breakdown of the essential features covered:

• Engine Type: The manual provides specifications for the diesel engine model, particularly focusing on the hydro engine.
• Application: It includes details specific to the 100 Hydro Tractor Engine, underscoring configurations related to hydro engine applications only.
• Component Details: Expect in-depth coverage of parts, assemblies, and subsystems involved in the overall functioning of the tractor’s diesel engine.
• Operational Guidelines: Insights into how the different components work together and guidelines for optimal maintenance and performance.

This manual is an invaluable resource for anyone looking to understand or service the engine of an International Harvester 656 tractor.

What types of transmissions are covered in the Farmall 656 Tractor Parts Manual (Chassis)?

The Farmall 656 Tractor Parts Manual (Chassis) includes detailed information on both gear and hydrostatic transmissions for the 656 model tractors, which are available in both gas and diesel versions. This manual provides comprehensive guidance on parts specific to each transmission type, ensuring you have the right tools to maintain or repair either configuration. Whether you’re dealing with a gear-driven or hydrostatic system, this manual covers all the necessary components and assembly details.

What does the International Harvester 656 Tractor Operators Manual fit?

The International Harvester 656 Tractor Operators Manual is specifically designed to be compatible with the International Harvester 656 Tractor models. These include the gas, liquid propane (LP), and diesel variants. It is suitable for both row crop and utility configurations. Additionally, the manual covers tractors with either hydrostatic or gear drive systems.

What were the differences in engine governance and power output between the 656 Hydro and gear-drive models?

The primary distinction between the 656 Hydro and gear-drive models lies in how their engines were governed and their resultant power outputs. Both the Hydro and gear-drive tractors offered either C-263 cubic-inch gasoline engines or D-282 cubic-inch diesel engines. However, the key difference was the Hydro models operated at higher engine speeds, governed at 2,300 rpm compared to the gear-drive models’ 1,800 rpm.

This increase in rpm directly impacted power delivery. The 656 Hydro managed to produce approximately 66 horsepower at the power takeoff, and about 52 horsepower at the drawbar, regardless of whether it was powered by diesel or gasoline. In contrast, the gear-drive models would exhibit different performance metrics due to their lower rpm setting.

What were the engine options available for the Farmall 656, and how did they compare in terms of power and efficiency?

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.

While both engines delivered similar horsepower, they offered distinct benefits. The C-263 gasoline engine provided a reliable power source suitable for various tasks. On the other hand, the D-282 diesel engine stood out with its increased torque, offering greater pulling power and better performance under heavy loads.

Moreover, the diesel engine boasted advantages in longevity and fuel efficiency, making it a preferred choice for those prioritizing long-term operational cost savings and durability. This balance between power and efficiency ensured that operators could choose an engine that best suited their specific needs and operational preferences.

How do the engines compare regarding fuel consumption and efficiency?

The D-282 diesel engine is more fuel-efficient compared to the C-263 gasoline engine, resulting in lower fuel consumption for similar workloads.

How do the two engines differ in terms of longevity and durability?

The D-282 diesel engine is noted for its longevity, offering a longer lifespan and greater durability than the C-263 gasoline engine.

How do the C-263 gasoline and D-282 diesel engines compare in terms of torque?

The D-282 diesel engine provides greater torque compared to the C-263 gasoline engine, enhancing its pulling power and performance under load.

How was speed selection and control achieved on the 656 Hydro tractors?

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 delve into the specifics of speed selection and control on the 656 Hydro tractors, imagine a system designed for precision and safety.

• Dual Levers for Control: Speed selection was managed with two levers on either side of the steering pedestal, akin to those on gear-drive models. The left lever allowed operators to slide the speed ratio control handle forward or backward, selecting variable forward or reverse speeds with ease.
• Neutral Safety Design: A horizontal step in the guide slot for the speed ratio selector ensured that the forward and reverse positions were separated clearly at the neutral point. This clever design prevented overshooting neutral, adding a layer of safety to operations.
• Inching Pedal for Precision: Despite the clutchless design, an inching pedal was included. This feature was not just for psychological comfort; it could dump hydraulic pressure for emergency stops, halting the tractor smoothly.
• Controlled Pressurization: Engineers implemented a system to gradually pressurize the pump as the clutch pedal was released. This simulated the controlled release of a mechanical clutch, initially added for safety and to make controls more intuitive. It also came in handy for precision tasks like creeping up to attachments or loader work.

By combining the innovative hydrostatic drive system with these user-friendly controls, the 656 Hydro tractors offered a nuanced driving experience that balanced technological advancement with practical usability.

How does the design accommodate the operator’s psychological comfort?

The inclusion of an inching pedal provides operators with a sense of control and comfort, ensuring smooth and reassuring operation.

What safety features are included in the speed control system?

A panic stop mechanism is included via an inching pedal, which dumps hydraulic pressure to stop the tractor. Additionally, gradual pressurization simulates clutch release for safe starts.

How is the neutral position designed to prevent overshooting?

The design includes a horizontal step at the neutral position, effectively separating forward and reverse positions to prevent overshooting.

How does the speed ratio control work?

The speed ratio is adjusted by moving a control handle forward or backward, allowing the operator to choose between forward or reverse speeds.

How is speed selected on the 656 Hydro?

Speed selection is managed with two levers placed on either side of the steering pedestal, similar to the controls on gear-drive models.