John Deere 8120 Tractor Parts
8120 parts and accessories
The John Deere 8120 tractor, manufactured from 2003 to 2006, is a workhorse known for its power and reliability on the farm. Equipped with a robust John Deere PowerTech 8.1L diesel engine producing around 200 horsepower, the 8120 offers a PTO horsepower of approximately 175. Its blend of power, versatility, and operator comfort made it a popular choice for row crop farming and heavy tillage operations.
The John Deere 8120 was introduced as part of the 8020 series, replacing the earlier 8010 models and offering improvements in performance and technology. Production spanned from 2003 to 2006. At its heart lies a John Deere PowerTech 8.1L 6-cylinder diesel engine, producing approximately 200 horsepower (149 kW) at the flywheel. The engine features a displacement of 496 cubic inches (8.1 liters) and is turbocharged for enhanced power and efficiency. Transmission options include a 16-speed PowerShift transmission providing smooth gear changes under load. The independent PTO delivers around 175 horsepower (130 kW) and offers both 540 and 1000 RPM speeds for versatility. The hydraulic system provides a flow rate of approximately 30 GPM (113.6 L/min), and is often configured with 3-4 remote valves. It features a Category III 3-point hitch with a lift capacity of around 9,921 lbs (4500 kg). The 8120 found common application in row crop operations like planting and cultivating corn and soybeans, as well as in hay production and heavy tillage tasks. Its heavier frame and powerful engine differentiate it from smaller models in the John Deere lineup, making it well-suited for demanding tasks.
Specifications
| Engine | John Deere PowerTech 8.1L 200 HP Diesel |
|---|---|
| PTO HP | 175 HP @ 540/1000 RPM |
| Transmission | PowerShift 16-Speed |
| Hydraulics | 30 GPM, 3-4 remotes |
| 3-Point Hitch | Category III, 9,921 lbs |
| Fuel Capacity | 125 gallons |
| Weight | 19,321 lbs |
| Years Produced | 2003-2006 |
Maintenance Tips
- Engine Oil & Filter: Change your engine oil and filter every 250-300 hours of operation, using the recommended John Deere oil specification. Regularly check the oil level to prevent engine damage.
- Hydraulic System: Inspect hydraulic hoses and fittings for leaks regularly. Change hydraulic fluid and filters according to the manufacturer's recommendations (typically every 1000-1200 hours) to maintain optimal performance.
- Fuel System: Use clean, high-quality diesel fuel. Replace fuel filters at recommended intervals to prevent fuel system contamination and ensure proper engine operation. Consider using a fuel additive during winter months to prevent gelling.
- Seasonal Storage: Before storing the tractor for an extended period, stabilize the fuel, change the engine oil and filters, grease all fittings, and disconnect the battery. Store the tractor in a dry, sheltered location.
History & Background
The John Deere 8120 was part of the 8020 series launched in 2003, representing an evolution in tractor design and performance. This model built upon the success of previous John Deere tractors, incorporating technological advancements and improved operator comfort. The 8120 played a significant role in modern agriculture, offering farmers a powerful and reliable solution for a wide range of tasks.
Frequently Asked Questions
What engine is in the John Deere 8120?
The John Deere 8120 is equipped with a John Deere PowerTech 8.1L 6-cylinder turbocharged diesel engine producing approximately 200 horsepower.
What is the PTO horsepower on a 8120?
The John Deere 8120 has a PTO horsepower rating of approximately 175 HP and offers both 540 and 1000 RPM PTO speeds.
What oil filter fits the 8120?
The John Deere 8120 typically uses a John Deere oil filter part number RE504836. Cross-references include Baldwin BD7153 and Fleetguard LF9009.
What are common parts needed for the 8120?
Common wear parts for the John Deere 8120 include engine oil filters, fuel filters, hydraulic filters, air filters, fan belts, hydraulic cylinder seal kits, steering components (tie rod ends), clutch discs (if applicable) and PTO shaft components.

RE64509 - High Compression Piston Piston Liner Kit
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RE520036 - Rear Crankshaft Seal
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T20129 - Valve Stem Cap
SKU: T20129
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T20077 - Valve Keeper
SKU: T20077
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RE62777 - Exhaust Manifold; Outer (2/Pack) Gasket
SKU: RE62777
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RE62776 - Exhaust Manifold; Inner Gasket
SKU: RE62776
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RE61812 - Air Intake Temperature Sensor
SKU: RE61812
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SKU: RE61253
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SKU: RE57604
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RE57603 - Torsional Damper
SKU: RE57603
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RE57054 - Camshaft W/ Tappets
SKU: RE57054
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RE55475 - Head Gasket
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RE542461 - Exhaust Manifold Pressure Sensor
SKU: RE542461
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RE537635 - Manifold Air Temperature Sensor
SKU: RE537635
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RE535300 - Crankshaft
SKU: RE535300
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RE534314 - Crankshaft
SKU: RE534314
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RE534183 - .011 Undersize Thrust Bearing
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