Choosing Between the John Deere 4620 and 4630 for Box Blade Work

[MikePhua]

The Legacy of the 20 and 30 Series Tractors
John Deere’s 20 and 30 Series tractors, produced during the late 1960s through the early 1980s, represent a golden era of mechanical simplicity and raw horsepower. The 4620 was introduced in 1971 as a turbocharged upgrade to the 4520, offering around 150 PTO horsepower. The 4630 followed in 1973, part of the Sound Guard Body lineup, and brought improved operator comfort, better cab insulation, and a more refined hydraulic system. Both tractors were built for heavy fieldwork—plowing, disking, and pulling large implements—and continue to serve in grading, hauling, and land-leveling roles decades later.
Sales of the 4620 were modest compared to the 4630, which benefited from Deere’s aggressive push into cab comfort and power shift technology. The Sound Guard cab, introduced with the 30 Series, became a defining feature of Deere’s design philosophy and remains one of the most praised operator environments of its time.
Box Blade Compatibility and Power Requirements
A 10-foot box blade is no small implement. It demands substantial weight and torque to maintain consistent grading, especially in clay-heavy soils or when cutting through compacted terrain. Both the 4620 and 4630 offer sufficient horsepower and hydraulic capacity to handle such a blade, but subtle differences in transmission and cab design may influence operator preference.
Key terminology:

• Box blade: A rear-mounted implement used for grading, leveling, and spreading material. It features adjustable scarifiers and a reinforced cutting edge.
  
• PTO (Power Take-Off): A shaft that transfers engine power to implements.
  
• MFWD (Mechanical Front-Wheel Drive): Enhances traction, especially in uneven or wet conditions.
  
• Sound Guard cab: Deere’s enclosed operator station with integrated HVAC and noise insulation.
  

Transmission Options and Field Behavior
The 4620 commonly came with the 8-speed Synchro Range transmission, a reliable and straightforward gearbox that allowed clutchless shifting within ranges. The 4630 offered more variety, including the Quad Range and Power Shift options. While the Quad Range provided more gears, some operators found its shifting clunky during road transport. The Power Shift, though smoother, could become expensive to repair if internal components failed.
Field anecdotes suggest:

• The 8-speed Synchro is preferred for simplicity and durability.
  
• Power Shift is ideal for loader work and frequent speed changes.
  
• Quad Range offers versatility but may be overkill for box blade grading.
  

One operator recalled hauling manure daily with a 4630 Power Shift that had over 20,000 hours. Despite its age, the transmission held up well, though repairs were costly when they eventually came due.
Cab Comfort Versus Visibility
The Sound Guard cab on the 4630 provides excellent insulation, effective heating and cooling, and enough quiet to hear a radio while working. However, visibility—especially to the rear and sides—can be limited compared to open station models. For box blade work, where frequent glances at the blade edge and material flow are necessary, this tradeoff matters.
Pros of cab:

• Protection from dust, heat, and cold
  
• Reduced operator fatigue
  
• Integrated controls and better ergonomics
  

Cons of cab:

• Reduced rear visibility
  
• Maintenance challenges with aging HVAC systems
  
• Slightly larger footprint in tight grading areas
  

Some operators opt to replace the entire A/C system in older cabs, budgeting around $2,000 for a full retrofit. This ensures reliable climate control and avoids chasing leaks or electrical faults in 50-year-old components.
Hydraulic Performance and Steering Behavior
Both tractors rely on transmission-driven hydraulic pumps. In earlier models like the 4320, holding the clutch too long could cause hydraulic pressure to drop, disabling steering and implement control. This quirk was addressed in later models, but it remains a consideration for operators accustomed to long idle periods or frequent stops.
Recommendations:

• Avoid holding clutch at stops—shift to neutral and use brakes
  
• Inspect hydraulic lines and filters annually
  
• Upgrade to higher-flow pumps if using hydraulic box blade tilt or angle features
  

Alternative Models and Modern Comparisons
Some operators suggest considering newer models like the Case IH Magnum 7120 or 7130. These offer full powershift transmissions, better visibility, and more refined hydraulics. However, they also come with increased electronic complexity and higher purchase costs.
For those committed to the Deere legacy, the 4630 offers a balance of power, comfort, and parts availability. The 4620, while slightly older, remains a workhorse with fewer electronics and a simpler drivetrain.
Conclusion
Both the John Deere 4620 and 4630 are capable of pulling a 10-foot box blade with authority. The choice comes down to transmission preference, cab comfort, and maintenance philosophy. If visibility and simplicity matter most, the 4620 may be the better fit. If operator comfort and hydraulic refinement are priorities, the 4630 with a Sound Guard cab stands out. Either way, these machines prove that even decades-old iron can still sculpt land with precision and power.