Gehl 6640E Skid Steer Troubleshooting

The Gehl 6640E skid steer loader is powered by 190 cu.in (3.1 L) Deutz BF4M2011 4-cylinder turbocharged liquid-cooled diesel engine with a rated power of 82 hp (61 kW) at 2500 rpm. The Gehl 6640E is equipped with a single-speed or two-speed hydrostatic transmission, 100 roller drive chains, and 12x16.5-10 or 14x17.5-12 tires. The hydraulic system has a pump with fluid flow rate of 23 gpm (87.1 lpm). The hydraulic pressure is 3000 psi (207 bar). The skid steer loader has a rated operating capacity of 2600 lbs (1180 kg) and tipping load of 5200 lbs (2360 kg). The lift height is 124.3 inches (3155 mm) to hinge pin, and dump height is 94.8 inches (2410 mm).

Engine Troubleshooting

Engine hard to start or will not start

Air trapped in fuel system - Bleed air.
Fuel filter element is clogged - Change the filter element.
Fuel injection nozzles are faulty or clogged - Inspect nozzles and replace if necessary.
Water in the fuel system - Change fuel and repair fuel system.
Valve out of adjustment - Check and adjust.
Fuel injection pump damage - Rebuild or install a new injection pump.

Engine starts and then shuts off

Air filter is plugged - Clean or change filter.
Fuel filter plugging - Replace the filter element.
Fuel injection pump leakage - Check the fuel injection pump for leaks and fix it.
Clogged or defective injectors - Change or clean fuel injectors.
Fuel injection pump is not operating properly - Replace injection pump or repair it.

Engine stalls after running

Engine is not fully warmed up - Warm up the engine as required.
Dirty fuel filter - Clean the filter or install new filter element.
There is air in the fuel system - Bleed the system.
Fuel injection nozzles are damaged or dirty - Check and replace nozzles if required.
Improper fuel injection timing - Adjust fuel injection pump as required.

Engine stops at low idle speed

Low idle speed adjustment is incorrect - Adjust low idling as recommended.
Defective fuel injection pump - Rebuild or install a new injection pump.
Fuel injector fault - Inspect fuel injectors and change as required.
Incorrect valve clearance - Adjust valve clearance according to specifications.

Engine loses power

Dirty air cleaner - Clean or replace element.
Damaged or dirty injection nozzles - Change fuel injection nozzles.
Fuel injection pressure is incorrect - Adjust pressure to proper level.
Valve clearance is wrong - Check and adjust.
Incorrect low idle speed adjustment - Adjust the low idle speed.
Dirty fuel lines or hoses - Clean fuel hoses and lines.
Cylinder head gasket is worn - Install a new gasket.
Leaking or damaged piston rings - Piston rings need to be replaced.

Engine overheating

Insufficient coolant fluid - Top up coolant fluid and check system for leaks.
Insufficient engine oil - Fill up the oil to required level.
Dirty radiator core or defective radiator cap - Replace cap or clean radiator.
Broken or loose fan belt - Belt change is required.
Diesel engine is overloaded - Load reducing required.

Oil pressure is insufficient

Low crankcase oil level - Checking oil level and add if necessary.
Oil filter clogging - Clean or replace engine oil filter element.
Improper type of engine oil - Drain and refill with oil of correct grade and viscosity.
Crankshaft bearing oil clearance is incorrect - Bearing needs to be changed.
Oil pump malfunction - Replace as required.

Engine noises or knocks

Engine oil insufficient - Fill the crankcase with engine oil.
Engine has not warmed up to required temperature - Warm up the engine as required.
Improper setting of fuel injection pump timing - Adjust fuel injection pump as required.
Low idle speed adjustment is incorrect - Adjust the low idle speed.
Fuel injectors are faulty or clogged - Clean or replace fuel injectors.
Connecting rod misalignment or failure - Need to align or replace the connecting rod.
Pistons are scored or worn - Install new pistons.

Drive System Troubleshooting

Drive system doesn't operate in one direction or either direction

Low hydraulic fluid level - Fill the system to proper hydraulic fluid level.
Drive chain failure - Inspect drive chain and replace faulty parts.
Damaged input drive shaft - Rebuild or change.
Relief valve defective or worn - Repair or install a new relief valve.
Clogged hydraulic filter or suction line - Replace hydraulic filter or clean suction line.
Foot or hand controls are damaged - Inspect and repair if necessary.
Damaged drive pump or motor - Replace or repair faulty component.

Lack of power

Hydraulic oil filter is plugged - Change or service hydraulic filter.
Relief valve is defective or open - Replace or close relief valve.
Worn or defective transmission parts - Inspect and change faulty parts.
Stuck input drive shaft - Replace or service the drive shaft.
Air in the hydraulic system - Air bleeding is required.

Drive system is overheated

Hydraulic oil level is low - Need to add oil.
Hydraulic fluid filter is dirty - Change hydraulic filter.
Relief valve worn or defective - Change or repair relief valve.
Defective drive pump or hydraulic motor - Change or repair faulty component.
Dirty oil cooler - Clean the cooling fins.
Transmission overloading - Reduce the load.

Drive system is noisy

Wrong oil viscosity - Use oil of proper viscosity.
There is air in the hydraulic system - Bleed air from system.
Defective drive pump or hydraulic motor - Check and repair if required.
Worn or damaged mechanical parts of drive system - Inspect the parts and repair as required.

Hydraulics Troubleshooting

Hydraulic system has overheating

Hydraulic pressure is not adjusted correctly - Adjust pressure as required.
Main relief valve is faulty or misadjusted - Adjust or replace the relief valve.
Hydraulic fluid is dirty - Change hydraulic fluid.
Lack of hydraulic oil - Fill up the hydraulic oil.
Hydraulic pump is faulty - Repair or install new hydraulic pump.

Lift arm won't raise or lower

Lift controls failure - Repair or replace.
Hydraulic pump failure - Change or repair hydraulic pump if required.
Hydraulic control valve malfunction - Replace or repair the valve.
Hydraulic cylinder is defective - Change or repair lift cylinder.
Low hydraulic oil level - Checking hydraulic oil level and add if necessary.

Bucket does not tilt

Faulty bucket tilt controls - Change or repair.
Hydraulic pump malfunction - Install new pump or repair it.
Hydraulic control valve failure - Install a new hydraulic valve or repair it.
Damaged bucket cylinder - Replace or repair cylinder.
Hydraulic oil level low - Need to add oil.

Slow bucket or lift arm action

Hydraulic pump is defective - Test pump performance and replace pump if necessary.
Hydraulic cylinder leaking - Repair leak by replacing the seals.
Hydraulic fluid is insufficient - Fill up the hydraulic fluid.
Hydraulic control valve is faulty or out of adjustment - Repair or set properly.
Hydraulic pressure loss - Adjust pressure correctly.

Lift arm or bucket jerks when working

Air leaks in hydraulic system - Air bleeding is required.
Hydraulic oil filter is dirty - Clean or replace the filter.
Contaminated hydraulic fluid - Hydraulic fluid change required.
Scored cylinder tube or rod - Replace worn component.

Hydraulic pump is noisy

Not enough oil or hydraulic system leaking - Top up hydraulic oil or remedy leakage in system.
Hydraulic filter clogging - Clean or change the filter.
Suction line is clogged - Clean suction line as required.
Air in hydraulic pump - Bleed air.
Worn pump components - Replace or rebuild the pump.

Electrical Troubleshooting

Battery cannot be charged

Corroded or loose cable connections - Service or tighten connections.
Battery terminal clamps are faulty - Change terminal clamps.
Battery failing - Change the battery.
Damaged or loose belt - Belt needs to be adjusted or replaced.

Starter motor turns slow

Low battery power - Battery is drained, recharge it.
Battery won’t hold charge - Service charging system or change battery.
Bad battery terminals or disconnected wiring - Connect cables correctly or replace terminals.

Starter is not cranking

Battery is drained or worn - Charge or change the battery.
Wire harness is disconnected or incorrectly connected - Check wire harness and connect as required.
Low battery power - Charge the battery.
Faulty starter motor - Repair or install a new starter.