Problems with your brush hog gearbox will usually trace back to lubrication and operating conditions. If you’ve got low gear oil, that will add strain and wear to the mower’s parts. Also check for blade damage or a loose stump jumper because problems elsewhere in the cutting system can impact the load on the drivetrain.

If you only use your brush hog to trim pasture several times a year, it has a light workload, so it probably doesn’t need the same frequent inspection schedule as it would if you were reclaiming overgrown acreage every weekend. Basically, the harder the attachment works, the closer you should watch the parts that support the gearbox.

Here are a few operation and upkeep tips to set your inspection schedule.

1. Lubricate the Brush Hog Gearbox Often

Gear oil is the first priority if you want to get a long service life out of a brush hog gear box. Our Prime Industrial Brush Mower uses a 90-degree Omni Gearbox with standard 80W-90 gear lubricant. There should be one liter of gear oil in the gearbox and its recommended to change oil every 100 hours, not exceeding 200 hours.

A good rule of thumb is to change your gear oil every year or every other year, depending on usage. If you wait until there’s a terrible noise or poor performance, you’re in for some repairs. A few minutes with the gearbox now definitely beats a dead brush hog on mowing day.

2. Inspect Hydraulic Hoses Before You Hook Up

Pressure sometimes builds up inside hydraulic hoses — and even more so in hot weather. We always recommend you check your hoses and fittings for leaks before each use. Tighten up any connections that need attention.

If pressure prevents hookup, follow the proper pressure-relief procedure for your machine before you reconnect the attachment.

3. Keep the Blades Sharp

Dull or damaged blades force your mower to take extra time as it works through material, and it’ll put more strain and wear on the gearbox.

Inspect your brush mower blades often for any visible damage and sharpen them roughly every 20 operating hours. That’s a broad guideline…the exact interval will depend on what you’re doing. If you do a lot of work on rocky ground or a lot of tree brush removal, do more frequent checks. If you’re mowing the lawn, you can probably stretch the time longer.

The Prime Industrial Brush Mower handles material up to 3 inches in diameter, so keep up with blade condition checks if you plan to hack through woody growth with your badass brush hog.

4. Always Check the Stump Jumper

The stump jumper connects the cutting assembly to the gearbox shaft, so any looseness underneath the deck will need immediate attention.

Inspect it real quick before each project. The pan should be tight against the tapered gearbox shaft, and the retaining cotter key should be securely in place. If you notice movement between those components, stop and tighten it up before you mow.

5. Respect Your Mower’s Intended Workload

A standard gearbox like you see on our Prime Brush Mower is rated for trees up to 3 inches. Our design uses a light blade-and-flywheel assembly for quicker spool-up. It’s a badass gearbox, but it won’t be right for every job.

Let’s say you want to hack through trees up to 8 inches thick. That’s above the intended workload for the standard mower, but you could opt for the Prime Direct Drive Mower and hack away! The four blades and 417-pound flywheel on our direct drive model will take down those trees in a jiffy.

6. Set Your Maintenance Schedule by the Hours You Mow

Your brush hog might spend a month or two in the shed, then work for a week straight on a huge pasture reclamation job. Don’t set a rigid maintenance schedule — it might be too slow for some intervals and quicker than necessary at other times. A fixed calendar is a poor substitute for hours in service.

Track operating hours — again, 20 hours in service is a good baseline inspection interval — and shorten your intervals if your mower spends more time in demanding material.

Ready for the Next Cut? Call Prime.

If your workload calls for a new mower, check out the popular Prime Attachments standard gearbox Industrial Brush Mower and our heavier Direct Drive Mower for tougher clearing work.

Questions? Talk with Prime Attachments about the right mower for your property and machine.