Excavator Final Drive Problems

Don’t forget that the original machine manufacturers procedures should be followed where available.

Final Drive Breakdown?

If you have drive motor problems, or if your final drive is weak or won’t move, it doesn’t necessarily mean the cause of the fault is with the drive. Even if there is damage to the gearbox or motor, that damage could be the symptom of a fault elsewhere on the machine.

Here are some things to look for:

Is there sufficient oil in the hydraulic oil tank?
Does the engine run at full speed?
Are the tracks too tight?
Is the machine stuck in high speed mode?
Are the tracks, track rollers and idlers in good condition?
Is the machine delivering the correct oil pressure, and flow, to the track motors?
Are there any internal leakages in the swivel joint?
Is the excavator final drive leaking?
Is there back pressure, or a blockage in the motor case drain line?

Don’t run a repaired or replacement drive unless you are certain you understand the reason for the original failure — and have rectified the fault

Final Drive Troubleshooting

Work through the chart below to help to with excavator travel motor troubleshooting.

Symptom	Problem		Possible Cause	Solution
Oil Leak	Excavator final drive leaking oil from gearbox cover	1.	Distorted gearbox cover or casing caused by physical damage	Replace the cover and cover O-ring, have the casing machined to remove distortion
		2.	Pressure build-up in gearbox caused by motor or external problem	Contact your FDC Partner
	Oil leaking from behind the sprocket	1.	Damaged or worn floating (lifetime) seal	Replace the floating seal
		2.	Pressure build-up in gearbox caused by motor or external problem	Contact your FDC Partner
Gearbox oil level too high	Hydraulic oil leaking from the motor into the gearbox	1.	Worn motor shaft oil seal or bearings	Replace accordingly
		2.	Excessive pressure in motor casing	Contact your FDC Partner
Excessive noise	Insufficient oil in gearbox		Gearbox oil leak or lack of maintenance	Gearbox / motor requires overhaul
	Worn bearings or gears		Gearbox / motor has reached the end of its planned service life or failed through a lack of maintenance	Replace drive with new or reconditioned unit from the Final Drive Centre.
Excessive vibration	Sprocket loose		Sprocket bolts loose	Tighten or replace bolts
	The gearbox 'shudders' while turning		Gearbox / motor has reached the end of its planned service life or failed through a lack of maintenance	Gearbox / motor requires attention / overhaul
Excessive heating	Gearbox casing is hot to touch or steams when wet	1.	No oil	Add oil
		2.	Worn Bearings	Gearbox requires overhaul
		3.	Brake does not release properly	Check brake operating pressure and brake piston seals
		4.	Hydraulic oil excessively hot	Check oil cooler & hydraulic system
Excavator has one track faster or will not climb steep gradient or steers to one side or one excavator travel motor slow	Lack of power	1.	Hydraulic pressure low	Check hydraulic pressure at the travel motor
		2.	High external friction	Check track chain tension and condition of track rollers and idlers
		3.	Travel motor stuck in fast mode	Check speed control system
		4.	Travel motor excessively worn	Repair or replace travel motor
		5.	Gearbox excessively worn	Repair or replace gearbox
Drive does not turn	Motor works but not driving gearbox		Motor shaft or 1st sun gear broken	Replace both motor shaft and 1st sun gear (with coupling if required)
	Nothing turns	1.	Gearbox / motor has reached the end of its planned service life or failed through a lack of maintenance	Contact your FDC Partner
		2.	Brake does not release	Check braking system if external brake control fitted
		3.		Check brake piston seals if internal brake is fitted
Drive freewheels	Brake does not function	1.	Residual; pressure in circuit	Check hydraulic system
		2.	Worn brake discs	Replace discs
		3.	Broken motor shaft	Replace motor shaft

Excavator Final Drive Problems