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Gehl 4635 SXT Troubleshooting

The Gehl 4635 SXT skid steer loader is powered by 133 cu.in (2.2L) Deutz BF3M1011F three-cylinder vertical direct injection turbocharged liquid-cooled diesel engine with a rated power of 57 hp (42.5 kW) at 2500 rpm. The Gehl 4635SXT is equipped with a radial-lift loader boom, single-speed hydrostatic transmission, 80E drive chains, and 7.00x15 standard tires. The hydraulic system has a pump with fluid flow rate of 19 gpm (72 lpm). The skid steer loader has a rated operating capacity of 1425 lbs (646 kg) and tipping load of 2850 lbs (1292 kg). The lift height is 115 inches (2920 mm) to hinge pin, and dump height is 87.2 inches (2215 mm).

Engine Troubleshooting

Engine starts hard or won't start
Air in fuel tank - Bleed fuel tank.
Fuel filter plugging - Clean or replace the filter.
Damaged or dirty injection nozzles - Clean or replace injection nozzles.
Water or dirt in fuel system - Drain, flush, and service the system.
Valve clearance is wrong - Check and adjust.
Damaged fuel injection pump - Repair or change injection pump.

Engine starts but stalls immediately
Clogged air filter - Replace or clean air filter element.
Fuel filter element is clogged - Clean the filter or install new filter element.
Fuel injection pump is leaking - Repair any leaks.
Defective or clogged fuel injectors - Inspect fuel injectors and change as required.
Fuel injection pump is broken - Repair or change injection pump.

Engine shuts off suddenly during operation
Engine is not preheated - Normalize the temperature by warming up the engine.
Fuel filter is plugged - Clean or change the filter.
Air in fuel tank - Bleed fuel tank.
Faulty or dirty injection nozzles - Service or change injection nozzles.
Fuel injection pump timing is wrong - Set up as recommended.

Engine stalls when idle
Improperly adjusted low idle speed - Adjust the low idle speed.
Defective fuel injection pump - Repair or change injection pump.
Dirty or defective injectors - Clean or replace fuel injectors.
Improper valve clearance - Have it adjusted.

Lack of engine power
Air cleaner is dirty - Clean or change cleaner.
Fuel injection nozzles fault - Change fuel injection nozzles.
Fuel injection pressure is wrong - Adjust to proper pressure.
Excessive valve clearance - Check and adjust as required.
Too low idle RPM - Adjustment required.
Dirt in the fuel hoses or lines - Service fuel lines and hoses.
Damaged cylinder-head gasket - Replace cylinder head gasket.
Piston rings are worn or damaged - Piston rings need to be replaced.

Engine overheats
Insufficient coolant fluid - The cooling system needs to be refilled and checked for faults.
Engine oil insufficient - Need to add engine oil.
Radiator fins are clogged or radiator cap is faulty - Clean radiator or change cap.
Fan belt is loose or defective - Replace as required.
Engine is overloaded - Load reducing required.

Oil pressure is insufficient
Insufficient engine oil - Add oil to the engine crankcase.
Clogged oil filter element - Clean or change engine oil filter.
Different type of engine oil - Fill up with the proper oil viscosity.
Incorrect oil clearance in crankshaft bearing - Bearings need to be reinstalled.
Oil pump is damaged - Inspect and change as required.

Engine noise or knocking
Low engine oil level - Fill up the oil to required level.
Engine is not fully warmed up - Engine is not warmed up to the required temperature.
Improper fuel injection timing - Adjust according to specifications.
Low idle speed setting is not correct - Adjust low idle speed.
Defective fuel injectors - Inspect fuel injectors and change as required.
Faulty or misaligned connecting rod - Align or change connecting rod.
Pistons are worn or broken - Pistons replacement required.

Drive System Troubleshooting

Drive system doesn't operate in one direction or either direction
Insufficient hydraulic fluid - Checking hydraulic fluid level and add if necessary.
Drive chain failure - Inspect drive chain and replace faulty parts.
Worn or damaged relief valve - Relief valve need to be replaced or repair.
Hydraulic filter or suction line is clogged - Check, clean, or change if necessary.
Damaged or worn hand or foot controls - Replace or repair.
Damaged drive pump or motor - Repair or replace faulty component.

Lack of power
Clogged hydraulic oil filter - Check, clean, or change as necessary.
Relief valve is damaged or open - Change or close relief valve.
Faulty or damaged transmission components - Check and replace faulty components.
Stuck input drive shaft - Repair or install a new drive shaft.
Air in the hydraulic system - Need to bleed air.

Drive system overheats
Hydraulic oil is insufficient - Fill the system to proper hydraulic oil level.
Hydraulic fluid filter is clogged - Replace hydraulic filter.
Relief valve is worn or damaged - Change or repair defective relief valve.
Hydraulic motor or drive pump failure - Repair or replace faulty component.
Oil cooler is clogged - Cooling fins should be cleaned.
Drive system overload - Load needs to be reduced.

Drive system is excessively noisy
Wrong oil viscosity - Use the specified type of oil.
Air in the hydraulic system - Need to bleed air.
Damaged drive pump or hydraulic motor - Replace or repair faulty component.
Worn or defective mechanical components of drive system - Check drive system and change faulty components.

Hydraulics Troubleshooting

Hydraulic system is overheated
Incorrect hydraulic pressure setting - Adjust pressure correctly.
Defective or misadjusted main relief valve - Replace or set up the relief valve.
Contaminated hydraulic fluid - Fill up with fresh hydraulic fluid.
Not enough hydraulic oil in the system - Check oil level and add hydraulic oil as required.
Hydraulic pump is worn - Repair or install new hydraulic pump.

Lift arm cannot be raised or lowered
Lift controls are defective - Check and repair as required.
Hydraulic pump not working - Repair or change pump if required.
Hydraulic control valve is faulty - Change or repair hydraulic valve.
Hydraulic cylinder malfunction - Replace or repair boom cylinder.
Insufficient hydraulic fluid - Fill the system to proper hydraulic fluid level.

Bucket does not tilt
Bucket tilt controls malfunction - Repair or replace.
Hydraulic pump not working - Replace or repair pump if necessary.
Faulty hydraulic control valve - Install a new hydraulic valve or repair it.
Bucket cylinder malfunction - Repair or install a new cylinder.
Hydraulic fluid is insufficient - Fill up the hydraulic fluid.

Slow bucket or lift arm operation
Defective hydraulic pump - Test the pump flow rate and change pump if required.
Hydraulic cylinder oil leakage - Install new cylinder seals.
Hydraulic fluid is insufficient - Add fluid as required.
Faulty or incorrect setting hydraulic control valve - Repair or set correctly.
Hydraulic pressure has dropped - Set pressure correctly.

Lift arm or bucket movements are jerky
There is air in the hydraulic system - Need to bleed air.
Hydraulic oil filter element is clogged - Change or clean oil filter.
Hydraulic fluid contamination - Change hydraulic fluid.
Scored cylinder tube or rod - Change defective component.

Hydraulic pump is noisy
Hydraulic leakage or low oil level - Refill hydraulic oil or repair leaks in system.
Hydraulic filter clogging - Replace or clean the filter.
Suction line clogging - Suction line must be serviced.
Air enters the pump - Air bleeding is required.
Faulty pump parts - Rebuild or change hydraulic pump.

Electrical Troubleshooting

Battery will not charge
Wiring connections are corroded or loose - Clean or tighten wiring connections.
Battery terminal clamps are faulty - Install new terminal clamps.
Defective battery - Battery replacement required.
Loose or defective belt - Belt needs to be adjusted or changed.

Starter cranks slow
Low battery voltage - Low battery charging, charge as required.
Battery drains quickly - Service battery or replace it.
Wires are disconnected or battery terminals are corroded - Check wiring and clean or replace terminals.

Starter motor won't turn
Battery is low or faulty - Charge or replace the battery.
Wiring is incorrectly connected or disconnected - Inspect wiring and connect correctly.
Low battery capacity - Recharge the battery.
Faulty starter motor - Starter needs to be changed.