How to rebuild a Bush Hog Rotary Cutter gearbox.

[yanmars]

I also change the gear oil on occasion. My 6 foot Bush Hog just threw off one blade, I hope I do not have as much difficulty as you did.

 

[beemerphile]

A follow-up after a good bit of work with the Bush Hog. It is dead smooth. I can't tell the PTO is engaged until it snags some good sized brush or it bottoms on a dirt mound. I welded up some splits and cracked welds that I have accumulated over the years. The cut is almost finish mower smooth. I believe I may have gotten away with this after all!

 

[Gale Hawkins]

A follow-up after a good bit of work with the Bush Hog. It is dead smooth. I can't tell the PTO is engaged until it snags some good sized brush or it bottoms on a dirt mound. I welded up some splits and cracked welds that I have accumulated over the years. The cut is almost finish mower smooth. I believe I may have gotten away with this after all!

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Great save and a great cut.

We went back with new seals and oil when our gear box had to come off to repair the weld on the disk that holds the blades on. It was 40 years old and not leaking but we had to use some heat getting the spline off of the bottom of the gear box and hopefully that will never break again. Most of the weld had cracked years ago. If I had not found a stump we may have never known about the crack from years ago.

 

[mwayne]

Excellent work and thanks for sharing your knowledge.

 

[beemerphile]

Excellent work and thanks for sharing your knowledge.

Thanks. It didn't start out as knowledge. It started as a big mess to fix. But with the help of some good folks here and some old fashioned head-scratchin' it ended up as knowledge. Glad to share it.

 

[YLee Kioti]

Thanks for all the hard work involved in just posting this. Interesting read on the lack of oil changes.
Had I not x-threaded the plastic dip stick on the Rhino I may never have learned about the depth of condensation settling at the bottom of the lower bearing.
Got the new dip stick. Removed cover and used turkey baster to siphon out the oil.
It looked fresh out the bottle until I got to the bottom. Bottom bearing covered in vanilla colored oil/yuck.
So looks like part of the new spring ritual of slipping clutch will also be a total fresh gear oil replacement.

 

[TNhobbyfarmer]

I have much admiration for you gearheads who can take on and successfully complete such a project. Hats off to you.

 

[dieselscout80]

I have a question on this type gear box with straight cut gears.

Are the gears a matched set like a Ring and Pinion in a differential?

I have a mower gear box with straight cut gears where the output shaft (pinion) splines are worn.

The pinion is available separately, so could I just replace just the one gear as long as I maintain the backlash?

 

[Dave M7040]

I have a question on this type gear box with straight cut gears.

Are the gears a matched set like a Ring and Pinion in a differential?

I have a mower gear box with straight cut gears where the output shaft (pinion) splines are worn.

The pinion is available separately, so could I just replace just the one gear as long as I maintain the backlash?

The gears are not matched sets. If they were you could not order individual ones.

Watch for shims or special gaskets to set the meshing of the two gears.

Dave M7040

 

[dieselscout80]

The gears are not matched sets. If they were you could not order individual ones.

Watch for shims or special gaskets to set the meshing of the two gears.

Dave M7040

Thanks Dave. :thumbsup: