John Deere 8420 T
Built: 2002–2005 · Series: 8020er-Baureihe
More machines from model year 2002
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John Deere 8020 series (2002–2006) – the third generation of the big tractors from Waterloo: 8120 to 8520, the number as power step, T for the tracked version, PowerTech six-cylinder of 8.1 litres, 147 to 217 kW
The 8020 series followed the 8010s in 2002 and was the third generation of the big tractors with which John Deere had served the 200 to 300 hp class from Waterloo, Iowa, since 1994 – recognisable by the new cab, the Independent Link front-axle suspension and the engine with increased power. The type logic: 8 marks the series, the middle digit the power step – 8120 about 200 hp, 8220 220 hp, 8320 250 hp, 8420 270 hp, 8520 about 295 hp – 20 the generation, T the tracked version with rubber-belt undercarriage, represented in the register throughout from the 8120T to the 8520T. The engine in all models is the PowerTech six-cylinder of 8.1 litres at 2,200 rpm, with common-rail injection and power boost; the transmission is the 16-speed PowerShift, optionally with AutoPowr as stepless version.
Read on 3 more paragraphs
The register lists 7 versions with 147.2 to 217.1 kW from the six-cylinder of 8,134 cm³, torque from 857 to 1,030 Nm, unladen weights from 8,214 to 12,374 kg, lengths from 5,530 to 5,850 mm, widths from 2,540 to 2,634 mm and heights from 3,122 to 3,200 mm.
The 8020s are the tractors with which the tracked version gained a foothold in Europe – the 8420T and 8520T became the alternative to the Challenger in eastern Germany and Eastern Europe; in 2006 the 8030 series followed with a 9.0 litre engine.
On used tractors, operating hours, engine and common-rail injection, PowerShift transmission (clutch packs, oil history), Independent Link suspension, on T models the rubber belts, rollers and drive wheels, hydraulics and electronics and the service history at the Deere dealer count.
Sources: SpecCodex register, model data: John Deere 8020er-Baureihe, John Deere (Hersteller, Werk Waterloo)
Technical data
Engine
| Fuel | dieselcorrect |
|---|---|
| Power | 270 hp (198.7 kW)correct |
| Rated speed | 2,200 rpmcorrect |
| Cylinders | 6correct |
| Displacement | 8,134 cm³correct |
| Bore | 115.8 mmcorrect |
| Stroke | 128.5 mmcorrect |
| Compression ratio | 15.7correct |
| Cooling | water-cooledcorrect |
Dimensions and weights
| Length | 5,530 mmcorrect |
|---|---|
| Width | 2,634 mmcorrect |
| Height | 3,122 mmcorrect |
| Wheelbase | 2,260 mmcorrect |
| Ground clearance | 350 mmcorrect |
| Unladen weight | 11,965 kgcorrect |
Drivetrain and chassis
| Drive | track drivecorrect |
|---|---|
| Gearbox | 16V/4R or 16V/5Rcorrect |
| Forward gears | 16correct |
| Reverse gears | 5correct |
| Front tyres | 609, 6 x 2.261 mmcorrect |
| Rear tyres | 609, 6 x 2.261 mmcorrect |
| Top speed | 30 km/hcorrect |
Working data
| Fuel tank capacity | 492 lcorrect |
|---|
Origin and approval
| Construction | frame constructioncorrect |
|---|
Other data
| Linkage category | Cat III/IIIcorrect |
|---|
Where this model stands
Power-to-weight ratio: 16.6 kW/t (199 kW / 12 t)
Power class: Heavy (> 180 hp)
Stronger than 96% of the tractors in the register — out of 15,663 models with a stated power figure.
Calculated from the documented figures above — not a rating.
Frequently asked questions
How much power does the John Deere 8420 T have?
The John Deere 8420 T delivers 270 hp.
How much does the John Deere 8420 T weigh?
The unladen weight is 11,965 kg.
What engine does the John Deere 8420 T have?
6 cylinders, 8,134 cm³ displacement, Diesel.
How fast does the John Deere 8420 T go?
Top speed is 30 km/h.
What are the dimensions of the John Deere 8420 T?
5,530 mm × 2,634 mm × 3,122 mm.
When was the John Deere 8420 T built?
Production years: 2002–2005.
What to check before buying
- Check the hour meter against the service records — a replaced instrument is the most common gap.
- Compare the data plate and chassis number with the papers.
- Check the weights in the papers against the figures here — attachments change them.
- Check front and rear tyre sizes: mismatched pairs strain the drivetrain.
- Shift the gearbox cold and warm — jumps only show up at temperature.
- Load the hydraulics and watch for sag.
- Ask about parts availability for this build year — the running costs hang on it.
A general list for this type of machine — no substitute for an inspection or an appraiser.
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This page carries 27 individual figures for this model. They come from 1 recorded source; every figure can be traced there. What we cannot document is not here — we leave gaps open rather than estimate them.
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Other models in this series
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Tractor in 3D section
Turn the model, look inside and click an assembly — each one is explained.