EXCAVATOR FINAL DRIVE REMOVAL AND REPLACEMENT

Before you lift anything

Park on level ground and lower the bucket to the ground. Relieve hydraulic pressure and allow the oil to cool, because a travel motor that has been working holds heat for a long time. A final drive is heavy enough to need rated lifting equipment, so plan the lift before you break a single bolt and keep it supported at every stage. Have caps and plugs ready before you open any hydraulic connection.

Final drive disassembly and removal

Release the track

Loosen the sprocket nuts while the track is still tensioned, then release the track adjuster and remove or drop the track. Loosening the sprocket hardware first is far easier than fighting it once the drive is loose.

Open the undercarriage

Remove the cover plate from the track motor inside the undercarriage frame so the hoses and the mounting bolts are accessible.

Mark and disconnect the lines

Label every hose before it comes off. The travel lines, the two-speed pilot line and the case drain all look similar once the drive is on the bench, and a swapped line at refitting is one of the few mistakes that destroys a new unit immediately. Cap the hoses and plug the ports as you go. Contamination that enters here ends up inside the new motor.

Take the load, then unbolt

Support the assembly, remove the bolts that hold the drive to the track frame from inside, and withdraw the unit through the outside of the frame.

If it is seized

Do not hammer on the travel motor to free a stuck drive. The motor housing and the rotating group are not designed to take that, and you will turn a gearbox problem into a scrapped assembly. Work it out from the housing flange instead, with penetrating oil and patience.

Fitting the replacement

Refitting is the reverse sequence, with three points that decide whether the new drive survives.

Clean the mounting face

Any burr or trapped debris between the housing and the track frame will distort the housing when the bolts are pulled up.

Torque properly

Mounting and sprocket bolts are load-bearing. Use the figures on our bolt torque settings page rather than working by feel, and follow a diagonal pattern.

Connect the case drain correctly

Every piston motor leaks oil into its own casing by design, and the case drain line returns that oil to tank at low pressure. If that line is left off, blocked or plumbed into a pressurised return, pressure builds inside the casing and pushes the shaft seal out, taking the motor and often the gearbox with it. Check the line is clear and unrestricted before the machine moves. The full explanation is in what a case drain filter does.

Set the track before the machine works

Fill the new drive with the specified gear oil to the correct level, run the machine slowly with no load and check for leaks, then set track tension to specification. Over-tension is the fastest way to destroy a new final drive bearing, as explained in track tension and final drive damage. Then put the gear oil on a schedule using our gear oil change guide.

One job not to skip

If there was metal in the old drive, the debris is still in the hydraulic circuit and it will be pumped into the replacement. Flush the system first, following the flush procedure before a final drive replacement. This single step is the difference between a drive that lasts years and one that fails in months. Working on a specific machine? The model-level notes for Komatsu and New Holland are in replacing a final drive motor by model. Still deciding whether to replace at all, see rebuild or replace a final drive motor. New units for nearly 40 brands are in the final drive motors catalogue, shipped across the US and Canada.