| Manufacturer | John Deere |
| Price | - |
| Model | 8420 |
| Equipment Type | Row-Crop Tractors |
| Factory | Waterloo, Iowa, USA |
OCED TRACTOR TEST 1800 2
| Description | Diesel 16-speed 4WD May 7 - 31, 2002 Link: OCED Tractor Test 1800 file PTO performance Drawbar performance Gear 8 used for power test Gear 3 used for pull test |
| Max power | 207.49hp / 154.7kW |
| Fuel use | 13.6gal hour / 51.5l hour |
| Power at rated engine speed | 235.45hp / 175.6kW |
| Max pull | 29,964lbs / 13591kg |
JOHN DEERE 8420 POWER
| Engine (gross) | 284hp / 211.8kW |
| Engine (net) | 270hp / 201.3kW |
| Engine (max) | 314hp / 234.1kW |
| PTO (claimed) | 235hp / 175.2kW |
| Drawbar (tested) | 207.49hp / 154.7kW |
| PTO (tested) | 269.41hp / 200.9kW |
ENGINE DETAIL
The John Deere 8420 features a powerful turbocharged 8.1L inline 6-cylinder diesel engine, providing a strong rated power output of 270 hp (201.3 kW) at 2200 RPM, which is suitable for heavy-duty agricultural applications. With its electronic high-pressure common rail fuel system, it ensures efficient fuel management and compliance with Tier II emissions standards, although upgrades may be necessary for stricter regulations. Its robust design and high compression ratio of 16.5:1 yield excellent torque characteristics, making it an advantageous choice for tasks requiring sustained power, but potential challenges include managing engine heat due to high operating rates.
| Description | John Deere turbocharged diesel 6-cylinder liquid-cooled inline |
| Displacement | 496ci / 8.1L |
| Bore/Stroke | 4.56x5.06inches / 116x 129mm |
| Emissions | Tier II |
| Rated Power (ECE R24) | 270hp / 201.3kW |
| Rated Power (EC 97/98) | 284hp / 211.8kW |
| Maximum Power (ECE R24) | 300hp / 223.7kW |
| Maximum Power (EC 97/68) | 314hp / 234.1kW |
| Fuel system | electronic high-pressure common rail (HPCR) |
| Air cleaner | dry with secondary element |
| Compression | 16.5:1 |
| Rated RPM | 2200 |
| Idle RPM | 900-2300 |
| Operating RPM | 1500-2200 |
| Starter volts | 12 |
| Coolant capacity | 35.9qts / 34.0L |
ENGINE OIL
The John Deere 8420 tractor has an oil capacity of 28.5 quarts (27.0 liters), which allows for optimal lubrication and cooling of engine components. It’s advisable to perform oil changes every 250 hours of operation to maintain engine performance and longevity, ensuring contaminants are removed. Neglecting timely oil changes may lead to increased wear, reduced efficiency, and potential engine damage, making adherence to this maintenance schedule critical for operational reliability.
| Oil capacity | 28.5qts / 27.0L |
| Oil change | 250 h |
JOHN DEERE 8420 ENGINE
The John Deere 8420 is equipped with an efficient 8.1L 6-cylinder diesel engine, delivering optimal torque and horsepower for demanding agricultural tasks. Its advantages include improved fuel efficiency and enhanced power output, making it suitable for heavy field operations such as plowing and tilling. However, potential challenges may involve higher maintenance costs associated with larger engine components and the need for specialized service skills.
| Description | John Deere 8.1L 6-cyl diesel |
TRANSMISSION
The John Deere 8420 features a full power shift transmission with 16 forward and 4 reverse gears, allowing for smooth operation and efficient power management in various field conditions. The hydraulic wet disc clutch, combined with the Automatic PowerShift (APS), provides ease of use by enabling automated shifting that optimizes performance based on load. Key considerations include the significant oil capacity of 148 to 158.4 quarts, which supports robust cooling and lubrication, but may also require careful monitoring to avoid issues related to oil maintenance and quality.
| Transmission | John Deere PowerShift |
| Type | full power shift |
| Gears | 16 forward and 4 reverse |
| Clutch | hydraulic wet disc |
| Oil capacity | 148qts / 140.1L 158.4qts / 149.9L (ILS) |
| Description | Full power shift transmission with single shift lever with display on cab corner post. Tractor begins in 7 (forward) and 2 (reverse) on start up. Clutch pedal may be used to pre-select a gear by holding clutch and pressing lever until desired gear is reached. Automatic PowerShift (APS) allows automated shifting to match load |
SPEEDS
| Description | With 18.4R46 rear tires |
MECHANICAL
The John Deere 8420 features a 4x4 MFWD chassis, enhancing its traction on varied terrains, which is beneficial for heavy tillage and planting operations. Its hydrostatic power steering provides excellent maneuverability, while the hydraulic wet disc brakes ensure reliable stopping power even under load. The 16-speed full power shift transmission allows for smooth transitions between gears, optimizing engine performance and efficiency during diverse field tasks.
| Chassis | 4x4 MFWD 4WD |
| Steering | hydrostatic power |
| Brakes | hydraulic wet disc |
| Trailer brakes | hydraulic |
| Cab | Cab standard |
| Transmission | 16-speed full power shift |
CAPACITY
| Fuel | 160gal / 605.6L |
| Hydraulic system | 37gal / 140.0L |
| ILS Hydraulic system | 39.6gal / 149.9L |
| Front hubs | 3.6qts / 3.4L |
| ILS Front hubs | 4.2qts / 4.0L |
| Front diff. | 14.2qts / 13.4L |
HYDRAULICS
| Type | closed center pressure-flow compensated (PFC) |
| Capacity | 37gal / 140.0L |
| ILS Capacity | 39.6gal / 149.9L |
| Pressure | 2900psi / 200.0bar |
| Valves | 4 to 5 |
| SCV flow | 30gpm / 113.6lpm |
| Total flow | 33.5gpm / 126.8lpm *With standard 45cc pump 42.5gpm / 160.9lpm 57cc pump |
TRACTOR HITCH
| Rear Type | III/IIIN |
| Rear lift | 15180lbs / 6885kg 17300lbs / 7847kg |
| Front Hitch | IIIN |
| Front lift | 11000lbs / 4989kg |
POWER TAKE-OFF (PTO)
| Rear PTO | independent |
| Clutch | hydraulic wet discs |
| Rear RPM | 1000 (1.75)/540/1000 (1.375 optional) |
| Engine RPM | 540@1975 / 1000@2200 |
JOHN DEERE 8420 TIRES
The John Deere 8420, equipped with Ag front tires (16.9R30) and Ag rear tires (18.4R46), offers excellent traction and stability in various agricultural applications. The larger rear tires enhance weight distribution and reduce soil compaction, making it suitable for heavy tillage and row-crop operations. However, the tire size may limit maneuverability in tight spaces, which could be a challenge in smaller fields or orchards.
| Ag front | 16.9R30 |
| Ag rear | 18.4R46 |
DIMENSIONS
| Wheelbase | 118.9inches / 302cm 117.7inches / 298cm (ILS) |
| Length | 211.9inches / 538cm |
| Height (cab) | 122.2inches / 310cm |
| Front axle | Independent Link Suspension |
| Rear axle | Rack-and-pinion: 4.724 by 118.5inches / 119by 3009mm |
| 4WD Front tread | 60 to 80inches / 152to 203cm |
| ILS Front tread | 60 to 88inches / 152to 223cm |
JOHN DEERE 8420 WEIGHT
| Shipping | 21,650lbs / 9820kg |
| ILS Shipping | 23,050lbs / 10455kg |
| Operating | 23,780lbs / 10786kg (480/80R46 duals) |
| Max Drawbar | 3,900lbs / 1769kg (Cat 3 extended) 6,070lbs / 2753kg (Cat 3 short) 10,000lbs / 4536kg (Cat 4) |
DIMENSIONS & TIRES
The John Deere 8420 tractor, with a wheelbase of 118.9 inches (302 cm) or 117.7 inches (298 cm with ILS), optimizes stability and maneuverability in various agricultural applications, thanks to its robust design. Weighing between 21,650 and 23,780 pounds, it provides the necessary traction and ground engagement for heavy-duty tasks but may lead to soil compaction in sensitive environments. The combination of 16.9R30 front tires and 18.4R46 rear tires allows for versatile field performance, enhancing load-carrying capacity and improving traction in challenging terrains.
| Wheelbase | 118.9inches / 302cm 117.7inches / 298cm (ILS) |
| Weight | 21650 to 23780 pounds |
| Front tire | 16.9R30 |
| Rear tire | 18.4R46 |
8420 SERIAL NUMBERS
| Location | Serial number plate on rear of tractor |
| 2002 | 1001 |
| 2003 | 10001 |
| 2004 | 20001 |
| 2005 | 30001 |
ELECTRICAL
| Ground | negative |
| Charging system | alternator |
| Charging amps | 150 |
| Batteries | 2 |
| Battery CCA | 925 |
| Battery volts | 12 |