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Gehl 4635SX Troubleshooting

The Gehl 4635SX skid steer loader driveline system components: a 133 cu.in (2.2L) Deutz F3M1011F 3-cylinder naturally aspirated liquid-cooled diesel engine with a rated power of 44 hp (32.8 kW), and 1-speed hydrostatic transmission. The hydraulic system has a pump with a rated capacity of 19 gal/min (72 l/min). The system pressure is 2750 psi (190 bar). The Gehl 4635 SX is equipped with a radial-lift loader boom, 80E drive chains, and 7.00x15 standard tires. The skid steer loader has a max lift height of 115" (2920 mm) to hinge pin and dump height of 87.2" (2215 mm). The rated operating capacity is 1425 lbs (646 kg), and tipping load is 2850 lbs (1292 kg).

Engine Troubleshooting

Engine hard to start or will not start
Air trapped in fuel system - Bleed air.
Fuel filter plugging - Change the filter element.
Clogged or defective injection nozzles - Install a new kit of correctly balanced nozzles.
Dirt or water in fuel system - Drain water or flush dirt from the system.
The valve clearance is not adjusted - Adjust valve clearance according to specifications.
Fuel injection pump is not working correctly - Rebuild or replace pump.

Diesel starts and suddenly stops
Air cleaner is clogged - Service or replace air cleaner.
Clogged fuel filter - Change filter element.
Fuel injection pump leakage - Check the fuel injection pump for leaks and fix it.
Defective or clogged fuel injectors - Replace or clean fuel injectors.
Faulty fuel injection pump - Install a new pump or rebuild.

Engine stalls after running
Engine is not preheated - Normalize the temperature by warming up the engine.
Dirty fuel filter - Change filter element.
Air trapped in fuel system - Bleed air.
Fuel injection nozzles are clogged or faulty - If necessary, replace with a new nozzle.
Wrong setting of fuel injection pump timing - Adjust according to specifications.

Engine stalls while idling
Wrong adjustment of low idle speed - Adjust as required.
Fuel injection pump is not working correctly - Change or repair the pump.
Fuel injector fault - Inspect fuel injectors and change as required.
Incorrect valve clearance - Correct valve clearance.

Engine lacks power
Dirty air cleaner - Clean or replace air cleaner element.
Fuel injection nozzles fault - If necessary, replace with a new nozzle.
Fuel injection pressure is wrong - Correct the pressure settings.
Valve out of adjustment - Check and adjust as required.
Incorrectly set low idle speed - Adjust low idling as recommended.
Clogged fuel lines or hoses - Fuel hoses and lines must be clean.
Cylinder head gasket is worn - Gasket should be replaced.
Piston rings are worn or defective - Install new piston rings.

Engine overheats
Coolant level is low - The cooling system needs to be refilled and checked for faults.
Engine oil level low - Need to add engine oil.
Radiator fins are dirty or radiator cap is defective - Clean radiator or install new cap.
Fan belt is loose or defective - Fan belt must be replaced.
Diesel engine overloaded - Reduce engine load.

Oil pressure is low
Low oil level - Fill crankcase to proper oil level.
Engine oil filter is plugged - Clean or change engine oil filter.
Incorrect oil viscosity - Drain and refill with oil of correct grade and viscosity.
Incorrect oil clearance in main bearing - Install new bearings.
Oil pump failure - Repair or change.

Abnormal engine knocking or noise
Insufficient engine oil - Check and refill engine oil.
Engine is not warmed up to the required temperature - Warm up to required temperature.
Fuel injection pump timing is wrong - Adjust fuel injection pump as required.
Incorrect low idle setting - Correct low idle settings.
Fuel injectors are faulty or clogged - Replace fuel injectors.
Connecting rod is misaligned or defective - Need to align or replace the connecting rod.
Pistons are scored or worn - Pistons replacement required.

Drive System Troubleshooting

Machine does not move forward or backward
Low hydraulic oil level - Check and refill the hydraulic oil.
Damaged drive chain - Check drive chain and change defective parts.
Relief valve is stuck - Repair or replace relief valve.
Clogged hydraulic filter or suction line - Check, clean, or replace if required.
Defective foot or hand controls - Repair or replace.
Damaged drive pump or motor - Inspect and change as required.

Lack of power
Plugged hydraulic oil filter - Change or service hydraulic filter.
Open or faulty relief valve - Replace or close relief valve.
Transmission components are defective or worn - Inspect and replace faulty parts.
Stuck input drive shaft - Repair or replace drive shaft.
Air in hydraulic system - Air bleeding is required.

Drive system overheats
Low hydraulic oil level - Checking hydraulic oil level and add if necessary.
Clogged hydraulic fluid filter - Replace hydraulic filter.
Relief valver is broken - Service or change relief valve.
Hydraulic motor or drive pump is worn - Check and repair if required.
Hydraulic oil cooler is plugged - Cooling fins should be cleaned.
Drive system is overloaded - Load should be reduced.

Drive system is noisy
Improper oil viscosity - Drain and refill with proper oil.
There is air in the hydraulic system - Air bleeding is required.
Hydraulic motor or drive pump is worn - Check and repair if required.
Worn or defective mechanical components of drive system - Check drive system and change faulty parts.

Hydraulics Troubleshooting

Hydraulic system overheated
Hydraulic pressure incorrectly adjusted - Adjust pressure as required.
Main relief valve malfunction or improper adjustment - Adjust or change relief valve.
Dirty hydraulic oil - Hydraulic oil change required.
Lack of hydraulic fluid - Add fluid to the hydraulic system.
Hydraulic pump is defective - Replace or repair pump if necessary.

Boom won't lower or raise
Faulty lift controls - Repair or change.
Hydraulic pump is broken - Repair or change pump if required.
Hydraulic control valve failure - Repair or replace hydraulic valve.
Hydraulic cylinder malfunction - Repair or change hydraulic cylinder.
Hydraulic fluid level low - Fill up the hydraulic fluid.

Bucket fails to tilt
Defective bucket controls - Change or repair.
Hydraulic pump not working - Repair or change pump if required.
Hydraulic control valve is faulty - Repair or change the valve.
Hydraulic bucket cylinder not working - Change or repair cylinder.
Hydraulic fluid is insufficient - Fill the system to proper hydraulic fluid level.

Slow bucket or lift arm action
Hydraulic pump is worn - Test the pump performance and change pump if required.
Hydraulic cylinder oil leakage - Change cylinder piston seals.
Hydraulic oil level low - Checking hydraulic oil level and add if necessary.
Hydraulic control valve is faulty or out of adjustment - Repair or adjust correctly.
Hydraulic pressure loss - Adjust pressure as required.

Lift arm or bucket is moving jerkily
Air trapped in hydraulic system - Bleed hydraulic system.
Clogged hydraulic oil filter element - Service or change the hydraulic filter.
Hydraulic oil is contaminated - The oil must be changed.
Scratched cylinder rod or tube - Replace worn component.

Hydraulic pump is noisy
Lack of oil or hydraulic leakage - Remedy hydraulic leakage or refill oil as necessary.
Plugged hydraulic filter - Service or change hydraulic filter.
Dirty suction line - Need to clean the suction line.
Pump is sucking air - Bleed air from hydraulics.
Faulty pump components - Rebuild or change hydraulic pump.

Electrical Troubleshooting

Battery cannot be charged
Electrical wire connections are corroded or loose - Service or tighten cable connections.
Battery terminal connectors are faulty - Install new terminal connectors.
Dead cell in battery - Battery change required.
Worn or loose belt - Belt needs to be adjusted or changed.

Starter motor cranks slow
Battery voltage is low - Low battery charging, charge as required.
Battery does not hold charge - Battery needs to be serviced or replaced.
Disconnected wires or corroded battery terminals - Check battery wires and service or replace terminals.

Starter doesn't crank
Battery is drained or defective - Charge or change the battery.
Battery wiring is disconnected or improperly connected - Inspect wiring and connect as required.
Low battery output - Battery is drained, charge it.
Defective starter motor - Repair or change starter.