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John Deere 6620 Troubleshooting
The
John Deere 6620 Premium is a 6020 series 4x4 utility tractor. This model was
manufactured from 2001 to 2006. The John Deere 6620 tractor is powered by 414.4
cubic inches John Deere 6068T 4V-CR 4-stroke 6-cylinder turbocharged diesel
engine with a maximum power of 130 Hp (96.9 kilowatt) and 535 Nm (396 lb-ft) of
peak torque at 1700 rpm.
The John Deere 6620 Premium is equipped with 3 types of transmission.
Type 1: 24x24 PowrQuad Plus partial powershift transmission. Type 2:
24x24 AutoQuad transmission.
Type 3: AutoPowr variable transmission (IVT) with infinite forward and
reverse gears. Maximum travel speed (forward and reverse): 25 mph (40
km/h). The closed center hydraulic system with load-sensing control has
an axial-piston or gear-driven pump with a rated capacity of 25.4 gpm
(96.1 lpm). The main relief pressure is 300 bar (2900 psi). The John
Deere 6620 Premium is fitted with 420/70R28 front tires and 18.4R38 rear
tires. The wheel base is 104.3" (2640 mm). The tractor is compatible
with a John Deere 661 loader with a maximum lift height of 166 (4220),
or John Deere 731 loader with a lift capacity at full height of 4255 lb
(1930 kg).
| Engine Troubleshooting |
| Engine doesn't start or difficult to start |
| Fuel filter is dirty - Service or replace the filter |
| No fuel supply from the tank - Open the fuel supply valve |
| Air in fuel system - Air-bleed fuel system |
| Dirty or faulty injectors - Check fuel injectors and replace if required |
| Fuel injection pump damage - Replace or repair injection pump |
| Low engine compression - Inspect and replace faulty parts |
| Engine stops running while driving |
| Engine is not preheated - Warm up the engine |
| Air in fuel lines - Bleed fuel lines |
| Improper fuel injection - Fuel injection settings required |
| Dirty fuel filter element - Clean the filter or install new filter element |
| Dirty or faulty injectors - Check fuel injectors and replace if required |
| Engine starts and then stalls |
| Unadjusted fuel injection pump timing - Correct injection timing |
| Fuel filter is dirty - Clean the filter element |
| Fuel injector nozzles fault - Replace fuel injector nozzles |
| Fuel injection pump is defective - Install a new fuel pump or repair |
| Clogged air cleaner - Install new cleaner element or replace it |
| Engine shuts off while idling |
| Low idle speed setting is not correct - Need to adjust idle speed |
| Fuel injection pump is defective - Repair or install new pump |
| Fuel injector nozzles are dirty - Inspect injector nozzles and change if required |
| Excessive valve clearance - Have it adjusted |
| Insufficient coolant fluid - Add the coolant. Inspect the system for leaks |
| Cooling system components are defective or system is dirty - Flush cooling system or change faulty components |
| Engine oil insufficient - Add oil to the engine crankcase |
| Fan belt is broken or belt tension is unadjusted - Adjust belt tension correctly or change it |
| Thermostat fault - Test thermostat opening temperature, replace as required |
| Clogged fuel injectors - Test fuel injectors and change if necessary |
| Incorrect fuel injection pressure - Adjust to correct pressure |
| Clogged air filter element - Install new filter element or replace it |
| Engine oil filter is plugged - Service or change engine oil filter element |
| Diesel engine overloaded - Reduce the load or use a lower gear |
| Incorrect valve clearance - Have it adjusted |
| Improperly adjusted low idle speed - Adjust the low idle speed |
| Fuel pipes or hoses clogging - Clean fuel pipes and hoses |
| Poor engine compression: Valves are damaged or leaking - Have valves replaced |
| Engine knocking sound or abnormal noise |
| Timing of fuel injection pump is wrong - Fuel injection pump timing adjustment needs to be corrected |
| Fuel injector nozzles are clogged or faulty - Change or clean injector nozzles |
| Lack of engine oil - Add oil to the engine crankcase |
| Engine has not warmed up to the recommended temperature - Warm up engine as required |
| Crankshaft or main bearings wear - Install new parts |
| Damaged or defective piston rings - Install new piston rings |
| Flywheel bolts are loose - Bolts need to be tightened |
| Excessive engine oil consumption |
| External oil leaks: Worn seals or gaskets - Change to repair leaks |
| Incorrect oil viscosity - Fill up with the correct oil viscosity |
| Worn or broken piston rings - Piston rings need to be replaced |
| Worn valve guides and valve stems - Change the valves |
| Cylinder liners or pistons are worn - Inspect pistons and liners, replace as required |
| Electrical System Troubleshooting |
| Battery will not charge |
| Battery bad cell - Battery replacement required |
| Battery electrical wire harness failure - Inspect wires for defects, change or repair |
| Battery cables and terminals are corroded or loose - Cables and terminals must be tightened or cleaned |
| Belt wear or improper belt tension adjustment - Install new belt or adjust belt tension as required |
| Low battery output - Low battery charging, charge as required |
| Battery does not hold charge - Service charging system or change battery |
| Bad battery wiring harness - Inspect wiring for malfunctions, replace or repair |
| Loose or corroded battery terminals and cables - Tighten or service cables and terminals |
| Battery power is low - Battery is drained, charge it |
| Discharged or faulty battery - Charge or change the battery |
| Starter motor failure - Repair or replace starter |
| Wiring harness is disconnected or improperly connected - Check wiring harness and reconnect properly |
| Transmission Troubleshooting |
| Gear shift is hard |
| Worn or misadjusted clutch - Change or adjust clutch |
| Gear shift linkage is stuck or worn - Service or replace shift linkage |
| Worn or damaged shift forks - Replace the shift forks |
| Gearshift mechanism is worn out - Repair or replace worn components if required |
| Insufficient transmission fluid pressure |
| Lack of transmission fluid supply - Fill up the transmission fluid |
| Transmission oil filter element is clogged (if equipped) - Replace or service transmission oil filter |
| Relief valve failure - Replace the valve |
| Transmission is excessively noisy |
| Broken or worn bearings - Faulty bearings should be changed |
| Not enough fluid in transmission - Fill the transmission housing with fluid |
| Transmission fluid contamination - Change transmission fluid |
| Gears are defective or backlash is incorrect - Change worn gears or set backlash correctly |
| Worn or damaged shift forks - Change defective shift forks |
| Transmission fluid leakage |
| Seals or gaskets are damaged - Gaskets or seal need to be replaced |
| Transmission housing is cracked - Replace housing or transmission assembly |
| IVT Transmission Troubleshooting |
| Transmission makes noise |
| Insufficient transmission fluid level or contaminated fluid - Add the fluid to proper level or pour fresh fluid |
| Damaged or not adjusted speed control rod linkage - Replace rod linkage or adjust correctly |
| Damaged relief valve - Change relief valve |
| Excessive loading - Reduce loading |
| Defective or worn components of IVT transmission - Inspect transmission components and replace if necessary |
| Transmission oil overheated |
| Not enough oil in transmission - Correct the transmission oil level |
| Plugged transmission fluid filter - Change or service the transmission fluid filter |
| Cooling components are plugged or defective - Check all cooling components and change or clean if required |
| Transmission overload - Load needs to be reduced |
| Fluid level is low - Add transmission fluid as required |
| Insufficient charge pressure - Test charge pressure |
| Defective or worn relief valve - Install a new valve |
| Transmission fluid leaking |
| Gaskets or seals are broken - Install new components |
| High pressure inside the transmission housing - Change or repair damaged parts |
| Oil return tube is plugged - Check tube and clean if required |
| Hydraulics Troubleshooting |
| Hydraulic system overheats |
| Hydraulic system pressure is not set correctly - Set the hydraulic pressure as required |
| Unadjusted or defective main relief valve - Adjust or replace the relief valve |
| Contaminated hydraulic fluid - Change hydraulic fluid |
| Air leaks in hydraulic system - Check the pump seals, suction pipe, and fittings |
| Low hydraulic system pressure |
| Not enough hydraulic fluid in the system - Need to add fluid |
| Hydraulic oil filter element clogging - Clean the hydraulic filter or install new filter element |
| Hydraulic pump is faulty - Test pump performance and replace pump if necessary |
| Hydraulic control valve block is not set properly or defective - Adjust correctly or replace |
| Broken hydraulic cylinder - Check the hydraulic cylinder parts for damage or wear and replace if necessary |
| Hydraulic piping leaks - Find leaks in the system and fix it |
| Hitch cannot be raised or raising is too slowly |
| Not enough hydraulic oil in the system - Fill the hydraulic system with oil |
| Hydraulic fluid is too cold - Allow fluid to warm |
| Hydraulic oil filter is dirty - Service the hydraulic filter or change if required |
| Hydraulic pump is defective - Check pump flow and install new pump if necessary |
| Faulty or incorrectly adjusted main relief valve - Adjust or change relief valve |
| Defective or not adjusted hydraulic control valve - Adjust correctly or replace |
| Hydraulic cylinder is faulty - Check cylinder components for damage or wear and change if necessary |
| Suction pipe is broken or loose - Tighten the pipe or replace it |
| Hitch won't lower or lowers slowly |
| Hydraulic control valve block is not set properly or defective - Adjust properly or change |
| Hydraulic cylinder is defective - Check cylinder components for wear or damage and change if necessary |
| Worn hitch cross shaft - Install a new shaft |
| The hitch has mechanical faults - Change worn or defective hitch parts |
| Hitch jerks when drop or lift |
| Air enters in hydraulic system - Inspect the pump seals, suction pipe, and fittings |
| Hydraulic fluid is dirty - Hydraulic fluid change required |
| Hydraulic pump failure - Check hydraulic pump flow and replace pump if necessary |
| Hydraulic control valve is not set properly or defective - Adjust properly or change |
| Hydraulic cylinder failure - Check cylinder components for damage or wear and change if necessary |
| Steering System Troubleshooting |
| Steering wheel turns hard |
| Damaged or improperly installed steering column - Reinstall or replace the steering column |
| Air trapped in the steering system - Bleed the steering system |
| Not adjusted toe-in - Check toe-in and correct |
| Incorrect tire pressure - Inflate the tires correctly |
| Steering pump not working - Install a new steering pump |
| Hydrostatic steering unit has wear or damage - Inspect and replace as required |
| Not enough steering fluid - Fill up steering fluid to required level |
| Steering system has oil leaks - Tighten the steering hose and pipe joints |
| Steering wheel has too much free-play |
| Worn steering column coupling or shaft - Replace defective part |
| Hydrostatic steering unit is defective or worn - Change or repair steering unit if required |
| Steering pump failure - Check the hydraulic steering pump and change if necessary |
| Steering linkage or tie-rod ends are defective - Change damaged part |
| Front wheels wander to right or left |
| Tires are improperly inflated - Inflate as necessary |
| Toe-in adjustment is incorrect - Adjust toe-in properly |
| Faulty or worn steering linkage or tie-rod ends - Change damaged part |
| Damaged or worn hydrostatic steering unit - Change or repair steering unit if required |
| Steering cylinder malfunction - Change or repair steering cylinder |
| Worn or incorrectly adjusted or worn front hub bearings - Adjust correctly or change bearings |
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| Farm Tractors Technical Specifications |
