The Hard Life of a Final Drive
When it comes to your bulldozer or excavator, the final drives take the most pounding. It stands to reason why the final drives are the one part heavy machine owners will have to fix or replace the most.
Proper maintenance will extend the life of a final drive however, the part will eventually reach a point when there's no other option but to have it replaced.
And since the both final drives are doing virtually the same amount of work, it's inevitable when one final drive bites the dust, the other side will soon meet the same demise.
"It's generally accepted both final drives will fail within six months of each other," says Al Alexander of Conequip Parts.
The life of your final drives will of course depend on various factors such as how the machine is being used and how well you maintain the part.
A leading factor for final drive to crash is when one of the main bearings fails. It's the main reason a final drive's life comes to a bitter end.
When a final drive is vibrating and making a lot of noise, that is a good indication the drive is ready to fail.
Two more signs your final drive is failing is when the outer seal starts to leak or the gearbox is heating up too much.
Another problem source are the final drive gears, specifically the teeth. The tip of the gear tooth should be somewhat flat. Over time, the teeth get sharp. When they get worn down to a point, they need to be replaced.
Then there's the upper and lower shafts. Look for damaged gear splines and too much play. If the flattened surface of the shaft has been worn away until the teeth look pointed, it's time to replace the shaft.
The bearing can wear a groove in the gear plate. When that happen you should replace the gear plate or use lapping to restore the flat surface.
If you're going to rebuild your final drive you should also replace the seals and o-rings. This seems like common sense but when a floating seal can cost a thousand dollars or more, it may be tempting to cut that corner.
The most common cause of a final drive failure is a clogged drain filter. That is followed by a weak charge pump. If that pump is weak, it won't be able to provide enough hydraulic pressure to release the internal brake.
If you hear a loud squealing noise and your machine isn't moving like it should, you can bet your bottom dollar that's the problem.
Please know that if you change your final drive you need to change your charge pump or you face a good chance of damaging the new final drive.
CONEQUIP PARTS OFFERS DISCOUNTS AND
EXTENDED WARRANTIES WHEN A CUSTOMER BUYS 2 FINAL DRIVES
"Basic routine maintenance like checking the oil and replacing the case drain filter can extend the life of your final drive," says Ben Krentz Co-Owner of ConEquip Parts.
However, when one of your drives goes down for good, you can reasonably expect the second drive will die soon after. Definitely something to consider, especially if you are buying a new final drive and you are being offered a discount to purchase a second final drive.
Have a Question About a Final Drive?