John Deere 8420 Tractor Parts
8420 parts and accessories
The John Deere 8420 tractor, manufactured from 2002 to 2005, was a popular choice among farmers for its power and reliability. Powered by a robust John Deere PowerTech 8.1L diesel engine producing around 225 engine horsepower, the 8420 delivered impressive performance. With a PTO horsepower rating of approximately 185, it was well-suited for a variety of demanding agricultural tasks, making it a versatile workhorse on any farm.
The John Deere 8420 was part of the 20 Series tractors, introduced in 2002 as an upgrade from the previous John Deere 8010 Series. Production continued until 2005. The heart of the 8420 is a John Deere PowerTech 8.1L (496 cu in) six-cylinder turbocharged diesel engine. This engine delivers a rated 225 horsepower (gross) and around 185 PTO horsepower. The engine is known for its durability and efficient fuel consumption. Transmission options included the standard 16-speed PowerShift transmission, or the optional Infinitely Variable Transmission (IVT) for smooth, clutchless operation. The PTO features both 540 and 1000 RPM options, catering to various implement requirements. The closed-center hydraulic system offers a flow rate of approximately 41 GPM, providing ample power for hydraulic implements. The three-point hitch is a Category III/IIIN, capable of lifting around 10,500 lbs. The John Deere 8420 was commonly used for row crop operations, hay production, livestock management, and primary tillage. It distinguished itself from other models in the lineup with its increased horsepower and advanced features, bridging the gap between the smaller 8020 series and the larger, more powerful 9000 series tractors.
Specifications
| Engine | John Deere PowerTech 8.1L 225 HP Diesel |
|---|---|
| PTO HP | 185 HP @ 1000 RPM |
| Transmission | PowerShift, 16-speed |
| Hydraulics | 41 GPM, 3-4 remotes |
| 3-Point Hitch | Category III/IIIN, 10,500 lbs |
| Fuel Capacity | 150 gallons |
| Weight | 20,500 lbs |
| Years Produced | 2002-2005 |
Maintenance Tips
- Check engine oil and filter regularly, typically every 250-500 hours, using John Deere-approved oil and filters for optimal engine life.
- Inspect hydraulic fluid levels and filters every 500 hours, replacing filters as needed to prevent contamination and ensure proper hydraulic system performance.
- Maintain the fuel system by using clean fuel and changing fuel filters regularly (every 500 hours), draining any water from the fuel tank to prevent injector damage.
- Before seasonal storage, fill the fuel tank to prevent condensation, lubricate all grease fittings, and disconnect the battery to prevent discharge.
History & Background
The John Deere 8420 was introduced in 2002 as part of the redesigned 8020 series, replacing the 8410 model. It offered increased power and updated styling compared to its predecessor. The 8420 played a significant role in modern agriculture by providing farmers with a reliable and technologically advanced tractor for a wide range of tasks.
Frequently Asked Questions
What engine is in the John Deere 8420?
The John Deere 8420 is equipped with a John Deere PowerTech 8.1L (496 cu in) six-cylinder turbocharged diesel engine, producing 225 horsepower.
What is the PTO horsepower on a 8420?
The PTO horsepower on the John Deere 8420 is approximately 185 HP, typically at 1000 RPM, but it also has a 540 RPM option.
What oil filter fits the 8420?
The recommended oil filter for the John Deere 8420 is a John Deere filter part number RE504836. Common cross-references include Baldwin B7344 and Wix 57712.
What are common parts needed for the 8420?
Commonly needed parts for the John Deere 8420 include engine oil filters, fuel filters (John Deere RE522878), hydraulic filters (John Deere RE62419), fan belts, hydraulic cylinder seal kits, steering cylinder repair parts, and clutch components like discs and pressure plates.

AF4736 - Primary (QTY 1) Air Filter
SKU: AF4736
5 in stock

AF26357 - Cab Air (QTY 1) Filter
SKU: AF26357
12 in stock

AF26201 - Secondary Magnum RS (QTY 1) Air Filter
SKU: AF26201
1 in stock

AF26200 - Magnum RS (QTY 1) Air Filter
SKU: AF26200
2 in stock

AF1659 - Air (QTY 1) Filter
SKU: AF1659
1 in stock

TA20416 - RH ILS Suspension Cylinder
SKU: TA20416
39 in stock

TA20415 - LH ILS Suspension Cylinder
SKU: TA20415
63 in stock

RE62205 - Front Axle Rear Pivot Support
SKU: RE62205
16 in stock

RE62204 - Axle Support. Front Support W/ Bushing
SKU: RE62204
28 in stock

RE588328 - Steering/Drive Seal
SKU: RE588328
295 in stock

RE588241 - Front Axle Seal
SKU: RE588241
152 in stock

RE567107 - ILS Steering Cyl Seal Kit
SKU: RE567107
94 in stock

RE49315 - LH Axle Housing/Spur Gear Seal
SKU: RE49315
41 in stock

RE48761 - Cup & Cone Bearing Set
SKU: RE48761
Out of stock

RE321770 - ILS Suspension Hydraulic Accumulator
SKU: RE321770
Out of stock

RE299899 - Final Drive Seal
SKU: RE299899
62 in stock

RE294014 - MFWD Differential Disc
SKU: RE294014
209 in stock

RE294013 - MFWD Differential Disc
SKU: RE294013
6 in stock

RE287095 - LH Steering Cylinder
SKU: RE287095
62 in stock

RE287094 - RH Steering Cylinder
SKU: RE287094
62 in stock

RE250838 - Universal Joint With Shaft
SKU: RE250838
21 in stock

RE238667 - King Pin; MFWD Seal
SKU: RE238667
23 in stock

RE206146 - ILS Steering Cyl Piston Seal
SKU: RE206146
32 in stock

RE204264 - Transmission Oil Pressure Sensor
SKU: RE204264
151 in stock
