I destroyed the gearbox on my brush hog.... help

dkmc · Oct 2, 2023

Back in '93 I bought a well used but cheap Woods 5' hog that spent it's life behind a 100hp tractor. I think the owner never looked back when using it. No oil in it, and gears about 1/3 worn out. Brushogs take a beating and most are rolling demolition derby's. The blade shaft loosens up, the oil seal fails, oil leaks out and no one notices or checks the level. My lower bearing housing was cracked as well. I made a steel sleeve and pressed it onto the housing, installed 2 seals, set the bearing preload quite snug (you don't want that blade shaft loose or wobbling around, or it will destroy the seals). Also set the input shaft preload snug. Luckily this one came with the woods clutch which does help protect things a bit. After all the work and repairs, I filled it with: A gob of grease, a heaping table spoon of never seize, fill up with 85-140 gear oil. It's worked fine ever since, but I do check the lube level and don't abuse it toooo much. Gears are a bit noisy. Back then woods wanted $350 for a tail wheel. The arm was there but no wheel. I went to the junk yard and got a front strut off of a honda car, wheel and all. Made that fit and swivel, it's been on their ever since and haven't had a flat yet.

P113565 · Oct 2, 2023

ROUSTABOUT said:
Input shaft leaking, probably had a bearing problem. I have given gearboxes that size tee total heck. I mean the tractor on a 45 deg angle riding 3" trees over. Bunch of trees at a time. Still have that ole bush hog and it was a free gimme piece of skinned over junk when given to us when i was a kid, single digits. Mid fifties now,. Bush Hog still works, same one. Jimmy Carter was president when we got it, and it was old when we got it.

LittleBittyBigJohn said:
Put me down on the list that says get a gearbox and mow on. Looking at tractor data, your machine should have 45 hp at the PTO when new. I don't see that destroying a 40hp gearbox in the short or long term. I think LD1 has a good theory, pinon shaft backed out and extra backlash wore the gear set out.

This /\. Get a new gearbox w the same HP rating, ratio and mow on. Use correct shear bolts and you can do terrible things to it and it will keep on ticking. 40-45 HP makes no difference if the shear bolts are correct. As someone mentioned make sure that the blades swing on the stump jumper deck, And while you are at makes sure they are sharp too. The bolts are probably going to be tough to loosen, don’t be afraid to use a cut off wheel and replace them at the same time.