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.

RE193357 - Control Arm Seal
SKU: RE193357
55 in stock

RE154869 - Front Axle Seal
SKU: RE154869
142 in stock

RE14439 - Oil Seal
SKU: RE14439
120 in stock

R95119 - Steering Cylinder Pin; MFWD; Seal
SKU: R95119
266 in stock

R87047 - Durometer 70 O-Ring; 13.490" ID X 13.768" OD X .139" Thickness
SKU: R87047
135 in stock

R82908 - Separator Plate
SKU: R82908
193 in stock

R72090 - Bearing; MFWD Cup
SKU: R72090
547 in stock

R560122 - MFWD Planetary Pinion Gear
SKU: R560122
20 in stock

R557917 - ILS Upper Pivot Shaft
SKU: R557917
16 in stock

R542099 - ILS Special Locking Flange Nut
SKU: R542099
74 in stock

R537928 - Independent Link Suspension Cylinder Pin
SKU: R537928
39 in stock

R290015 - MFWD Pinion Carrier Oil Plug
SKU: R290015
50 in stock

R237713 - Bevel; MFWD Gear
SKU: R237713
228 in stock

R237709 - Bevel Pinion; MFWD Gear
SKU: R237709
109 in stock

R228144 - MFWD Planetary Gear
SKU: R228144
35 in stock

R179849 - Bearing Cup
SKU: R179849
149 in stock

R159931 - MFWD Planetary Ring Gear Hub
SKU: R159931
10 in stock

R134224 - MFWD Front Pivot Support O-Ring
SKU: R134224
75 in stock

R133564 - Rod End Pin; Steering Cylinder
SKU: R133564
21 in stock

R131511 - Differential Bevel Pinion Shaft
SKU: R131511
84 in stock

R130069 - MFWD Axle Housing Bushing
SKU: R130069
201 in stock

R125974 - Front Axle Support Bushing
SKU: R125974
50 in stock

R112954 - MFWD Steering Cyl. Attaching Seal
SKU: R112954
196 in stock

R111774 - Steering Column Pivot Bushing
SKU: R111774
299 in stock
