Clutch on a Modern Bushhog

Gary_Sharbonno · Jan 3, 2005

My bushhog is a Modern Model with a 65 hp gear box. My question is how can you tell if the slip clutch is working and is it adjustable? I have not had it apart but it does have a drum looking attachment on the shaft and then the PTO drive shaft.
The manual does not say how to ajust or service the slip clutch. I am using it on a Mahindra 2810. I know it is more bush hog than I need. That is why I want to be sure that the clutch will slip. I have had it completely stop the tractor engine on 2 different occasions.
Let me know what you all think.

Thank you in advance.
Gary

Indydirtfarmer · Jan 3, 2005

I do commercial bush hogging. I currently use Woods BB8400 mowers. They have a slip-clutch. I "service and inspect" them 2 or 3 times a year. What I do is loosen all the bolts on the clutch. I then "lock" the gearbox end of the driveshaft with a long bar through the u-joint yoke. Then I apply (VERY CAREFULLY) some power to the driveshaft, via the tractor PTO. That forces the clutch to slip. I let it slip for a few seconds. At that point, I re-tighten the bolts as directed in the Woods manual. That is about 1/2" of threads showing beyond the locknuts. I would contact the manufacturer of either your mower, or the clutch itself for the exact specs on your clutch.

They shpouldn't be set so tight as to stop your tractor, but seeing as to how your mower is rated far beyond that of the tractor, you may or may not be able to run it that loose. John

rdbrumfield · Jan 3, 2005

Being that your hog gear box is rated higher than your tractor, set up the clutch for your tractor. It will be somewhat less than the gearbox is capable of, but as long as when you hit something solid it will slip and not stall your tractor, it should be just right. I would rather have some slippage than replace parts in the tractor tranny. I would set if for slippage, and then tighten to where it is comfortable with the tractor. If you set to the mower specs and it is overrated for the tractor, you risk hurting the tractor.

Soundguy · Jan 3, 2005

Do be sure you have a slip clutch and not an over runnning coupler.. some people ( salesman) can't tell them apart.

Soundguy

Gary_Sharbonno · Jan 4, 2005

Thanks for the info. I think that I did not explain myself very well. The clucth is a brake drum looking afair. the unit is sealed completely, however it has a front cover that is removalbe which has about 8 allen screws in it. I was wondering if anyone knew what might be inside and how to adjust it before I take it apart.

As usual thanks for the replies.
Gary

Glenn9643 · Jan 5, 2005

Gary,

The way I'm reading this it sounds as if you might have an overrunning coupler rather than a slipclutch.

A picture of the overrunning coupler is here.

Hope this helps.

Picture of the slipclutch is here.

have_blue · Jan 5, 2005

Hi Gary,

Just because the cutter can bog the tractor does not mean the slip clutch is not working. Clutches usually guard against very high "shock" loads, which can far exceed PTO torque. I don't think they are supposed to slip under normal PTO load, even a load that bogs the tractor. When the tractor bogs, just mow in a lower gear. The clutch is more to protect the mower's gearbox, not the tractor.

I was wondering if my own "55 HP gearbox" clutch was slipping on my 35 HP tractor. I put some chalk marks on the plates to check it. To my surprise, it slipped a little almost every time I mowed... even though I didn't hit anything more than a few ant hills or big wads of cut grass.

MMM · Jan 5, 2005

I've never tried it, but this should determine which clutch you have. Either dog off pto shaft in front of clutch or engage pto with tractor stopped and try turning blades both directions. Overrun should allow free turn one way only, slip clutch neither way.

Gary_Sharbonno · Jan 6, 2005

Thanks for the info. Iwill take the clutch assemble apart and let you know what I find. I need to take a picture of the clutch and post it. It is not like any of the ones that has been shown in the forum. This unit is located at the gear box, and you can see no clutches or spings. The reason I am concerned is that I have hit stumps and it stopped the tractor cold. I do not want that to happen again for fear of breaking something. I will trash this unit before I break my tractor.
Gary