Planer Gearbox Oil Change

Some would say I have too much equipment squeezed into my one car garage shop. Maybe it’s my New York attitude, but I scoff at those who say they work hand tools because their space it small. I say if there’s a will, there’s a way.

One of my favorite pieces of equipment.
One of my favorite pieces of equipment is my Grizzly 15” planer. It has a segmented cutter head and will spit out just about any board with a beautiful, tearout free surface.

I was quite dismayed recently when I moved the planer out of the way to find that the plywood I had recently stacked besides it was oil stained at its base where it adjoined the planer. A quick investigation revealed the planer’s gearbox as the source of the oil.

That's not the right type of oil to finish a project with.
After a review of the Grizzly owner’s manual and a few days of worry, I took the infeed/outfeed gear cover off to expose the gearbox. Before changing the oil I tested the allen bolts which held on the gearbox face and found all of them to be loose and between ½ and ¼ turn from tight. I tightened them all and I hope this will stop the leaking of oil from the gearbox gasket.

The first step was to remove the top cover of the planer because the oil fill plug is so high, the only way to reach it is with a hose fed through the main planer body. Then I made a makeshift funnel out of tape and removed the oil drain plug into a graduated plastic cub. 12 ounces of oil came out of the gearbox. Because the total gearbox oil volume isn’t listed in the owner’s manual, I wasn’t sure if 12 ounces was good or bad.

Once the gearbox was empty, the drain plug was re-installed the area around it wiped of oil. Then I carefully fed in the 3/8” tube into the fill hole. I taped a funnel to the top of the tube and clamped it in place to the top of the planer body.

Then I slowly poured 12 ounces of fresh 80w-90w oil into the gear box. All 12 ounces disappeared into the infeed hole. So I then – ½ ounce at a time – continued filling the gearbox. When I got to 16 ounces, oil finally began to spill out of the infeed hole.

Reacting to the spilling oil I made a mistake. I unclamped the funnel, knowing I needed to pull the hose out of the hole and place it in the plastic cup to drain. What I forgot was that I needed to re-clamp the funnel end. It wasn’t until oil began to drip onto the planer bed from the cutter that I realized I had simply left the funnel to fall over and spill out.

Once this was all cleaned up, I put the fill plug in and re-assembled the infeed/outfeed gear and top covers. Then I started up the planer and ran a piece of scrap maple through it until it stopped coming out with oil residue on it.


Through that limited testing, the planer seems to be running smoothly again. Here’s hoping that tightening the gearbox face addresses the leak and the gears stay nice and lubricated as I get into the serious business of milling for the Bartop Arcade Cabinet.








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