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Gehl 4640 Troubleshooting

The Gehl 4640 skid steer loader is powered by 142.1 cubic inches (2.3 L) Deutz BF3M2011 three-cylinder direct injection turbocharged liquid-cooled diesel engine with a rated power of 60 hp (44.7 kW) at 2500 rpm. The Gehl 4640 is equipped with a single-speed or two-speed hydrostatic transmission and 10x16.5-8 or 12x16.5-10 tires. The hydraulic system has a pump with fluid flow rate of 19 gpm (72 lpm). The hydraulic pressure is 3000 psi (207 bar). The skid steer loader has a rated operating capacity of 1500 lbs (680 kg) and tipping load of 3000 lbs (1360 kg). The lift height is 115.5 inches (2935 mm) to hinge pin, and dump height is 89.5 inches (2275 mm).

Engine Troubleshooting

Engine difficult to start or won't start
Air in the fuel system - Air bleeding.
Fuel filter plugging - Replace filter element.
Fuel injection nozzles are faulty or clogged - Check injection nozzles and replace if required.
Water in the fuel system - Change fuel and repair fuel system.
Excessive valve clearance - Correct valve clearance.
Defective fuel injection pump - Replace or repair injection pump.

Diesel starts but then stops
Plugged air cleaner - Clean or change.
Fuel filter element is dirty - Clean or replace the filter.
Fuel injection pump has loose connections - Tighten the connections.
Clogged or defective injectors - Change or clean fuel injectors.
Faulty fuel injection pump - Rebuild or change fuel pump.

Engine stalls after running
Engine is not fully warmed up - Normalize the engine temperature.
Dirty fuel filter - Install new filter element.
Air in the fuel pipes - Bleed the fuel pipes.
Fuel injection nozzles fault - Service or change injection nozzles.
Timing of fuel injection pump is incorrect - Adjust fuel injection pump as required.

Engine stops while idling
Low idle speed setting is incorrect - Test and adjust.
Defective fuel injection pump - Rebuild or install a new injection pump.
Clogged or defective injectors - Replace or clean fuel injectors.
Valve clearance is out of adjustment - Correct valve clearance needs to be set.

Loss of engine power
Plugged air cleaner - Clean or replace element.
Defective or clogged injection nozzle - Change fuel injection nozzles.
Incorrect fuel injection pressure - Adjust to proper pressure.
Excessive valve clearance - Check and adjust as required.
Incorrectly adjusted low idle speed - Correct low idle adjustment.
Restricted fuel hoses or lines - Clean fuel system lines and hoses.
Cylinder head gasket defective - Cylinder-head gasket replacement required.
Piston rings are worn or damaged - Piston rings replacement required.

Engine overheats
Coolant level is low - Add coolant fluid to cooling system and also check it for leaks.
Engine oil insufficient - Add oil to the engine crankcase.
Defective radiator cap or clogged radiator fins - Clean radiator or install new cap.
Fan belt slipping or worn - Install new fan belt.
Diesel engine is overloaded - Load reducing is recommended.

Oil pressure is low
Oil level is insufficient - Checking oil level and add if necessary.
Oil filter clogged - Change or clean engine oil filter element.
Oil grade or viscosity is wrong - Drain crankcase and refill with correct oil.
Main bearing oil clearance is excessive - Bearing needs to be changed.
Oil pump is defective - Install a new pump.

Abnormal engine noise or knocking
Engine oil level is low - Fill up the engine oil.
Engine is not warmed up to required temperature - Warm up to required temperature.
Fuel injection pump timing is not adjusted - Adjust fuel injection pump as required.
Low idle speed setting is incorrect - Test and adjust.
Damaged or clogged injectors - Replace fuel injectors.
Misaligned or faulty connecting rod - Need to replace or align the connecting rod.
Pistons are scored or worn - Pistons replacement required.

Drive System Troubleshooting

Drive system won't operate in either direction
Hydraulic oil level is low - Fill the system to proper hydraulic oil level.
Damaged drive chain - Inspect drive chain and replace defective parts.
Input drive shaft malfunction - Replace or service the drive shaft.
Relief valve worn or defective - Repair or replace.
Suction line or hydraulic filter is plugged - Service suction line or replace hydraulic filter.
Damaged or worn hand or foot controls - Replace or repair.
Drive motor or pump is worn - Inspect and change as required.

Low power
Clogged hydraulic oil filter - Replace hydraulic filter.
Opened or defective relief valve - Replace or close relief valve.
Transmission parts are worn or defective - Inspect and replace defective parts.
Input drive shaft failure - Faulty drive shaft need to be replaced or repair.
Air leaks in hydraulic system - Need to bleed air.

Drive system overheats
Hydraulic oil level is low - Checking hydraulic oil level and add if necessary.
Hydraulic fluid filter is plugged - Replace hydraulic filter.
Relief valve is damaged or worn - Repair or replace.
Hydraulic motor or drive pump failure - Inspect and change as required.
Clogged hydraulic oil cooler - Cooling fins need to be cleaned.
Drive system overloaded continuously - Reduce loading.

Excessive noise
Oil viscosity is incorrect - Drain and refill with proper oil.
Air leaks in hydraulic system - Air bleeding is required.
Defective drive pump or hydraulic motor - Replace or repair faulty component.
Worn or damaged mechanical parts of drive system - Inspect the components and repair as needed.

Hydraulics Troubleshooting

Hydraulic system overheats
Incorrect hydraulic pressure setting - Adjust it correctly.
Faulty or improperly adjusted main relief valve - Set up or change the relief valve.
Hydraulic fluid is contaminated - Hydraulic fluid change required.
Hydraulic oil level is insufficient - Fill the hydraulic system with oil.
Hydraulic pump is faulty - Change or repair hydraulic pump if required.

Lift arm does not lower or raise
Lift controls malfunction - Check and repair as required.
Hydraulic pump failure - Repair or install new hydraulic pump.
Hydraulic control valve malfunction - Repair or change hydraulic valve.
Hydraulic cylinder malfunction - Repair or replace hydraulic cylinder.
Low hydraulic oil level - Check and refill the hydraulic oil.

Bucket fails to tilt
Bucket controls are faulty - Replace or repair.
Hydraulic pump malfunction - Install new pump or repair it.
Hydraulic control valve is faulty - Repair or change the valve.
Hydraulic bucket cylinder not working - Repair or change cylinder.
Insufficient hydraulic fluid - Add fluid as required.

Boom or bucket functions slowly
Worn hydraulic oil pump - Flow-rate hydraulic pump and replace pump if necessary.
Leaking hydraulic cylinder - Correct leakage by changing the seals.
Hydraulic fluid is insufficient - Fill the system to proper hydraulic fluid level.
Worn or unadjusted hydraulic control valve - Repair or set correctly.
Low hydraulic pressure - Correct adjustment is required.

Lift arm or bucket is working jerkily
Air leaks in hydraulic system - Need to bleed air.
Plugged hydraulic oil filter - Clean or replace the filter.
Dirty hydraulic fluid - Fill up with fresh hydraulic fluid.
Cylinder rod or tube is scuffed - Replace worn component.

Hydraulic pump is excessively noisy
Hydraulic leaks or lack of oil - Correct hydraulic leaks or top up oil as needed.
Hydraulic filter is dirty - Change or clean oil filter.
Dirty suction line - Need to service the suction line.
Air in hydraulic pump - Air bleeding is required.
Pump parts are damaged - Rebuild or change hydraulic pump.

Electrical Troubleshooting

Battery cannot be charged
Electrical wire connections are loose or corroded - Clean or tighten connections.
Battery terminal clamps are defective - Change terminal clamps.
Battery dead cell - Install a new battery.
Worn or loose belt - Install a new belt or adjust belt tension.

Starter cranks slowly
Low battery output - Recharge the battery.
Battery won’t hold charge - Battery needs to be serviced or replaced.
Disconnected battery cables or bad terminals - Check battery wires and service or replace terminals.

Starter motor is not working
Battery is discharged or defective - Battery needs to be recharged or replaced.
Wiring is improperly connected or disconnected - Check wiring and connect properly.
Low battery output voltage - Charge the battery.
Starter motor failing - Replace or repair starter.