Pencil Fuel Injector RE38087 RE36939 SE500821 for John Deere 440 4400 4500 590D 595D 690D
This fuel injector is a direct replacement unit designed for John Deere 440. It delivers a precise atomized fuel spray into the combustion chamber for efficient burning. When an injector fails, the affected cylinder runs lean — or doesn’t fire at all — which puts extra stress on the remaining injectors and can damage the catalytic converter over time.
Vehicle Compatibility
| Application | Details |
|---|---|
| John Deere Windrower | See product specifications |
| John Deere Combine | See product specifications |
| John Deere Tractor | See product specifications |
| John Deere Telescopic Handler | See product specifications |
| John Deere Forklift | See product specifications |
| John Deere Hi | Cycle |
| John Deere Sprayer | See product specifications |
| John Deere Cotton Stripper | See product specifications |
| John Deere Skidder | See product specifications |
| John Deere Excavator | See product specifications |
Replaces OEM Part Numbers
RE38087 • RE36939 • SE500821 • 28485 • RE36935 • RE36936 • Deere • Engine • 4039DF001 • 4039DF007 • 4039DF008 • 4039DFM01
Signs You Need a Replacement
If your equipment is showing any of these symptoms, the injectors & nozzle may be the cause:
- Black or gray exhaust smoke — especially noticeable under load or acceleration
- Rough or uneven idle — the engine shakes or vibrates at low RPM
- Engine misfire or hesitation — stumbling when you step on the throttle
- Poor fuel economy — filling up more often for the same work
- Knocking or nailing sound — metallic noise from the engine under load
- Fuel smell in engine oil — diesel leaking past the injector seat into the crankcase
Replace as a Set
Replacing injectors as a set is the standard practice. Mixing old and new injectors creates uneven spray patterns — the new unit works harder and burns out faster. On multi-cylinder engines, a single failing injector can reduce total output by 20 to 30 percent. When you pull the old injectors, inspect the seats and copper sealing washers. If the seats are pitted or the washers are crushed, replace them before installing the new units.
Frequently Asked Questions
Will this fit my John Deere 440?
Yes. This part is designed to fit the John Deere 440, 4400, 4500, 590D among other models listed in the compatibility table above. Verify your specific model and engine code before ordering to ensure the correct fit.
Can I cross-reference RE38087 with RE36939?
Yes. Both RE38087 and RE36939 are interchangeable OEM numbers for this part. They refer to the same component with the same specifications, just different part number revisions. This replacement fits all applications listed for either number.
What are the common failure signs on a John Deere engine?
On John Deere engines, watch for black exhaust smoke under load, rough idle, misfire codes (P0300 series), and loss of power. A single failing injector can reduce engine output by up to 25%. If you notice fuel in the engine oil, the injector seat seal is likely compromised — replace it immediately to prevent crankcase contamination.
What tools do I need to install this on a John Deere?
Standard metric hand tools will handle most of the job — sockets, wrenches, and a torque wrench. For John Deere equipment, check the specific service manual for any special tools or torque values. Some diesel injector jobs may require a puller to remove the old unit.




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