Rotary Cutter Bush Hog Gear Box Leaking

[TNhobbyfarmer]

I am leaking gear oil out of the gear box of my cutter. Has anyone changed the seal on one of these gear boxes? Is it a very difficult job? Thank you for your input.

 

[Farmwithjunk]

I am leaking gear oil out of the gear box of my cutter. Has anyone changed the seal on one of these gear boxes? Is it a very difficult job? Thank you for your input.

Front seal or bottom? Front is an hour job, tops. Piece of cake. Bottom isn't cake.

First you'd need to remove the stump jumper. Could be a hard job, OR, it could be a horrendous job. Not fun at best. That exposes the seal... re-install everything.

Alternative... Run heavy grease in place of gear oil. It's done all the time. If the seal leaks out the grease, you're no worse off. If it DOESN'T leak, start mowing.

 

[greg_g]

I am leaking gear oil out of the gear box of my cutter. Has anyone changed the seal on one of these gear boxes? Is it a very difficult job? Thank you for your input.

The bottom seal on my 3 year old IM602 started leaking last summer, but not from actual use. I'd put it away after mowing - and the deck was dry. Come back the next time I needed it, dirty gear oil fouling the deck.

Finally dawned on me that the hot Kentucky sun in July/August was heating up the inside of the transmission case. Because the fill plug was unvented, the expanding contents had to go somewhere. The oil level wasn't high enough to push out the top seal, so it came out the bottom.

Solution; a three dollar vented fill plug. But if you come back and say you've already got a vented fill plug.....then brace yourself for a seal change.

//greg//

 

[mark4Jesus]

Greg G reminded me when the Bush Hog SQ480 I had started leaking oil. Bush Hog brands have vent plugs in the top. If you take it out and hit it in the palm of your hand you should feel the relief spring vibrate, if not then you need to clean it. I soaked mine in mineral spirits for about 30 min. and that freed it up. If the leak is from overpressurizing of the gearbox then you will be in good shape if the seal itself has not been damaged. Good Luck!

 

[greg_g]

Come to think of it, you're right - mine rattles when I shake it. Guess that means it's never gotten plugged up on me yet. I'll stick that in my memory banks for future reference. Thanks

//greg//

 

[RalphVa]

I'd try changing the gear oil first. You can probably suck or syphon it out through the vent hole if you remove the vent. Then put new in. If it isn't leaking very much, this often stops it from leaking for quite a while.

Ralph

 

[TNhobbyfarmer]

Front seal or bottom? Front is an hour job, tops. Piece of cake. Bottom isn't cake.

First you'd need to remove the stump jumper. Could be a hard job, OR, it could be a horrendous job. Not fun at best. That exposes the seal... re-install everything.

Alternative... Run heavy grease in place of gear oil. It's done all the time. If the seal leaks out the grease, you're no worse off. If it DOESN'T leak, start mowing.

Heavy gear grease? Exactly what type of grease are your referring to? Regular old grease that I put in zerk fittings or something more specialized?

 

[vallyfarm]

Yup. Plain old grease gun grease. You could spend a little mor and get a bettter grade, but "farmer's grease", the cheap stuff you use for the disc bearings, will do. If you want to go the extra mile, go to the local JD dealer and get a few tubes of Corn head grease. This is a little thinner, yet still a solid, but will flow in the bearings a bit better. You will need 2-3 tubes depending on the size of the gear box. Those tubes don't hold as much as you would think. Mike

 

[gizmo]

I have a very old FMC brand bushhog that had a leaking lower seal. For a couple years I just topped off the oil before I used it. When I finally decided to change the seal I was completely unaware of the adventure I was embarking on. This cutter is in my estimate about 40 years old. The blades are attached to a solid bar instead of stump jumper. Anyway, it required a high quality puller, a 3/4" impact driver, a torch, and a drift pin from the top side of the cutter driven with a 16# sledge. Once the blade bar was off the shaft I could easily remove the gear box. I then had to disassemble the gear box to get the shaft out followed by the shaft seal. The old seal had to be visually matched as the part number could not be cross referenced. I learned a lot, but I still question whether it was worth all the trouble verses topping it off occasionally.

 

[sandman2234]

I had one that I tried to change, ended up selling the durn thing for scrap when the gearbox when south on me. I couldn't get the stumpjumper off, so I kept filling it with 90wt before using it. Guess the leak got worse or I used it just a hair too long.
Changing the lower seal can be a job! I built a gear puller just for bush hogs and sometimes it wouldn't work and it was over built to say the least.
David from jax