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John Deere 4020 Troubleshooting

The John Deere 4020 is a 4x2 New Generation series row-crop tractor. This model was manufactured from 1963 to 1972. The components of JD 4020 driveline system: The John Deere 6-cylinder gasoline or diesel engine, and 8x4 Syncro Range partially synchronized transmission or 8-speed full power shift transmission. Max. forward speed - 20.5 mph (33 kph), max. reverse speed - 5.2 mph (8.4 kph).

The closed center hydraulic system includes a piston pump with fluid flow rate of 18 gpm (68.1 lpm). The main relief pressure is 2250 psi (155 bar). The rear lift capacity is 3790 lbs (1720 kg).

The John Deere 4020 tractor fitted with standard 7.5x18 front tires and 18.4x34 rear tires, or row-crop 6.00x16 front tires and 15.5x38 rear tires. The wheelbase is 100.3" (2540 mm) for standard models and 97.5" (2470 mm) for row-crop models. The John Deere 4020 is compatible with JD 148 front end loader with a maximum lift height of 126" (3200 mm), and JD 158 front end loader with a maximum lift height of 156" (3960 mm).

Diesel Engine Troubleshooting
Diesel won't start or hard to start
Fuel filter is dirty - Change the filter element
The fuel shut-off valve is closed - Open fuel shut-off valve
Air trapped in fuel system - Bleed air
Dirty or damaged injectors - Service or change fuel injectors
Fuel injection pump is defective - Repair or replace injection pump
Bad engine compression - Inspect cylinder block and replace worn components
Engine stalls during operation
Engine has not warmed up to the recommended temperature - Warm up the engine
Air in fuel pipes - Bleed fuel pipes
Irregular fuel injection - Adjust fuel injection timing
Plugged fuel filter - Service or replace the filter
Fuel injectors are damaged or dirty - Change fuel injectors
Engine starts and stalls immediately
Fuel injection pump out of timing - Adjust the fuel injection pump timing correctly
Dirty fuel filter element - Install new filter element
Clogged or defective injector nozzles - Check and change nozzles as required
Fuel injection pump is not operating properly - Repair or change injection pump
Air cleaner element is dirty - Change or replace air cleaner element
Engine stops while idle
Low idle speed setting is incorrect - Correct low idle settings
Fuel injection pump is not working correctly - Replace or rebuild injection pump
Clogged or damaged injector nozzles - Change or clean injector nozzles
Valve clearance is out of adjustment - Have it adjusted
Engine overheats
Engine coolant is insufficient - Fill radiator to proper level. Any leaks must be repaired
Cooling system parts are damaged or system is dirty - Replace faulty parts or flush the cooling system
Low engine oil level - Fill the crankcase with engine oil
Damaged fan belt or incorrect belt tension - Adjust belt tension properly or replace it
Defective thermostat - Check and replace if required
Engine lacks power
Fuel injectors are clogged or faulty - Inspect fuel injectors and replace if necessary
Improper fuel injection pressure - Check the fuel injection pressure and adjust if necessary
Dirty air filter element - Replace filter or install new filter element
Clogged oil filter - Clean or replace engine oil filter element
Engine is overloaded - Load reducing required
Valve clearance is out of adjustment - Correct valve clearance
Low idle speed setting is incorrect - Correct low idle adjustment
Fuel pipes or hoses are clogged - Clean fuel pipes and hoses
Lack of compression: Valves are defective or worn - Replace the valves
Engine noise or knocking
Incorrect setting of fuel injection pump timing - Repair or replace fuel injection pump
Clogged or defective injector nozzles - Install new set of properly balanced nozzles
Engine oil level low - Fill up the oil to required level
Engine is not fully warmed up - Engine is not warmed up to the required temperature
Main bearings or crankshaft wear - Install new parts
Broken or worn piston rings - Piston rings replacement required
Flywheel mounting screws are loose - Tighten the screws
Diesel engine consuming too much oil
Oil leaks: Damaged seals or gaskets - Worn parts need to be replaced
Incorrect oil viscosity - Use correct viscosity oil
Piston rings are seized or worn - Piston rings need to be replaced
Valve guides or stems are damaged - Valves replacement required
Cylinder liners or pistons are damaged - Check liners and pistons, replace as required

Electrical System Troubleshooting
Battery cannot be charged
Faulty cell in battery - Install a new battery
Damaged battery wiring harness - Inspect wiring for damage, replace or repair
Loose or corroded cables and terminals - Tighten or service cables and terminals
Belt is damaged or belt tension is incorrectly adjusted - Change belt or adjust belt tension properly
Starter turning slow
Battery voltage is low - Battery is drained, recharge it
Battery does not hold charge - Service charging system or replace battery
Bad battery wiring harness - Inspect wiring for malfunctions, replace or repair
Battery cables and terminals are corroded or loose - Clean or tighten cables and terminals
Starter will not work
Battery voltage is low - Low battery charging, charge as required
Drained or worn battery - Recharge or change battery
Starter motor is damaged - Starter should be replaced
Disconnected or incorrectly connected cables - Need to reconnect cables correctly

Transmission Troubleshooting
Gear hard to shift
Worn or incorrectly adjusted clutch - Adjust correctly or replace
Gear shift linkage is stuck or worn - Service or change the shift linkage
Shift forks are worn or damaged - Change the shift forks
Gearshift mechanism failure - Change or repair failed components
Transmission fluid pressure is insufficient
Low transmission fluid level - Fill up the transmission fluid
Transmission oil filter clogging (if fitted) - Change or clean the transmission oil filter
Damaged relief valve - Change relief valve
Transmission is excessively noisy
Bearings are worn or damaged - Replace faulty bearings
Oil level is low - Check transmission oil level and add oil as required
Transmission fluid contamination - Fill up with fresh transmission fluid
Worn gears or improper backlash - Change damaged gears or adjust backlash properly
Damaged or worn shift forks - Replace the shift forks
Transmission oil leaks
Broken gaskets or seals - Seals and gaskets replacement required
Transmission case is cracked - Replace case or transmission assembly

Hydraulics Troubleshooting
Excessive hydraulic system heat
Hydraulic system pressure is not set correctly - Set the hydraulic pressure as required
Unadjusted or defective main relief valve - Adjust the valve or replace if necessary
Hydraulic oil contamination - Change the oil
Aeration in hydraulic system - Check the pump seals, suction pipe, and fittings
Hydraulic oil pressure is insufficient
Hydraulic fluid level is low - Need to add fluid
Hydraulic fluid filter element is dirty - Clean or change hydraulic filter
Hydraulic pump is defective - Test the pump flow rate and change pump if required
Hydraulic control valve block is faulty or out of adjustment - Set properly or replace
Hydraulic cylinder is faulty - Check the cylinder components for damage or wear and change if necessary
Hydraulic piping leaks - Identify leaks in the system and repair it
Hitch cannot be lifted or lifting is too slow
Lack of hydraulic fluid - Check and refill the hydraulic fluid
Hydraulic oil is too cold - Allow oil to warm
Hydraulic fluid filter is dirty - Hydraulic filter maintenance required
Hydraulic pump is defective - Test the pump flow rate and change pump if required
Misadjusted or defective main relief valve - Adjust the valve or replace if necessary
Hydraulic spool valve is defective or set improper - Change or adjust correctly
Hydraulic cylinder is faulty - Check the hydraulic cylinder parts for damage or wear and replace if necessary
Damaged or loose suction line - Tighten or change
3-point hitch fails to drop or drops slowly
Defective or incorrect setting hydraulic control valve block - Adjust properly or change
Hydraulic cylinder is defective - Inspect the hydraulic cylinder parts for damage or wear and replace if required
Worn hitch rock shaft - Install a new shaft
Defective mechanical parts of the hitch - Replace worn or faulty hitch parts
Jerky lowering or lifting of the hitch
Air trapped in the hydraulic system - Inspect the pump seals, suction line, and fittings
Dirty hydraulic oil - The oil must be changed
Hydraulic pump is defective - Check pump capacity and change if necessary
Defective or not adjusted hydraulic control valve - Change or adjust correctly
Faulty hydraulic cylinder - Check cylinder components for wear or damage and change if necessary

Steering System Troubleshooting
Difficult steering
Steering column is broken or incorrectly fitted - Steering column needs to be refit correctly or replaced
Air trapped in the steering system - Bleed air
Improper toe-in adjustment - Adjust toe-in properly
Tires are incorrectly inflated - Inflate as required
Steering pump stopped working - Install a new steering pump
Steering valve assembly is damaged or worn - Replace or repair steering valve as required
Damaged steering valve cylinder parts - Replace defective components of steering valve cylinder
Steering fluid level low - Checking steering fluid level and add it if necessary
Oil leakage in the steering system - Retighten joints of the hydraulic steering pipes and hoses
Excessive free play of steering wheel
Steering column shaft or coupling has maximum wear - Replace defective part
Steering valve assembly is defective or worn - Repair or change the steering valve
Damaged steering valve cylinder parts - Defective steering valve cylinder components must be replaced
Steering pump not working - Repair or replace steering pump
Steering linkage or tie-rod ends are defective - Replace failed component
Tractor pulls to left or right
Tire pressure is improper - Inflate the tires properly
Improper toe-in adjustment - Adjust toe-in wheels properly
Faulty or worn steering tie-rod ends or linkage - Change damaged part
Faulty or worn steering valve assembly - Inspect and replace as required
Steering valve cylinder is faulty - Change or repair steering valve cylinder
Front hub bearings are worn or incorrectly adjusted - Adjust properly or change bearings




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