How Does Rotary Cutter Gearbox Work?

  May 23, / Rotary Cutter Gearbox...What to use? #1  

Iplayfarmer

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Idaho

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Massey Ferguson , Case 801B

I just got my old used rotary cutter up and running. Now a few questions about lube in the gearbox.

What should I use to top off my rotary cutter gear box?
Does universal tractor fluid work?
Do I need to drain and change this fluid periodically?
How full should the gearbox be?   May 23, / Rotary Cutter Gearbox...What to use?

• Thread Starter

#2  

Iplayfarmer

Super Member

Joined

Jul 11,

Messages

5,263

Location

Idaho

Tractor

Massey Ferguson , Case 801B

I just got my old used rotary cutter up and running. Now a few questions about lube in the gearbox.

What should I use to top off my rotary cutter gear box?
Does universal tractor fluid work?
Do I need to drain and change this fluid periodically?
How full should the gearbox be?   May 23, / Rotary Cutter Gearbox...What to use? #3  

beenthere

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Southern Wisconsin, USA

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JD_4x2_Gator, JD_, JD_425, JD_455 AWS, added JD_455, JD_110, JD_X485(sold)

I'd get a sample of what is in there first, and check it for 'dirt' and stiffness. Sometimes, heavy gear oil is used and on occasion, people put grease in them (as in grease-gun grease). Check for water as well. Then you can decide if you can get by adding gear oil or if you should drain it out and begin with new gear oil.
Usually there is a plug on the side of the box to check the oil level. Look for a steel plug with a 1/4" square head (pipe plug) that you can remove. If the gear oil is at that height, it is ok. I'd be careful not to tighten that plug REAL tight, as they can be a b**** to get out and don't need to be much more than finger tight.   May 23, / Rotary Cutter Gearbox...What to use? #4  

beenthere

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Southern Wisconsin, USA

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JD_4x2_Gator, JD_, JD_425, JD_455 AWS, added JD_455, JD_110, JD_X485(sold)

I'd get a sample of what is in there first, and check it for 'dirt' and stiffness. Sometimes, heavy gear oil is used and on occasion, people put grease in them (as in grease-gun grease). Check for water as well. Then you can decide if you can get by adding gear oil or if you should drain it out and begin with new gear oil.
Usually there is a plug on the side of the box to check the oil level. Look for a steel plug with a 1/4" square head (pipe plug) that you can remove. If the gear oil is at that height, it is ok. I'd be careful not to tighten that plug REAL tight, as they can be a b**** to get out and don't need to be much more than finger tight.   May 23, / Rotary Cutter Gearbox...What to use? #5  

Highbeam

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South Puget Sound, WA

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Kioti CK30HST

My gearbox uses 90 weight gear oil. Not UTF. If there's water in it, you'll get a nice grey/brown milkshake right away. If you see the milkshake then change the oil. You can remove the fill plug and then tip the mower over on its side to drain it out. The gearbox doesn't hold much oil and it won't hurt a thing to change it. If you are going to change it I would run it and get all the sediment stirred up first so that it comes out with the old oil.   May 23, / Rotary Cutter Gearbox...What to use? #6  

Highbeam

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South Puget Sound, WA

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Kioti CK30HST

My gearbox uses 90 weight gear oil. Not UTF. If there's water in it, you'll get a nice grey/brown milkshake right away. If you see the milkshake then change the oil. You can remove the fill plug and then tip the mower over on its side to drain it out. The gearbox doesn't hold much oil and it won't hurt a thing to change it. If you are going to change it I would run it and get all the sediment stirred up first so that it comes out with the old oil.   May 23, / Rotary Cutter Gearbox...What to use? #7  

rdbrumfield

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JD 4X4

I run a bush hog, 6ft, and it calls for 90wt. Lost the lower seal many years ago, replaced it and filled with a good grease. I put some 90 in with it and drilled a small hole in the filler plug to vent. Haven't had a problem with it, and I use it regularly, and hasn't leaked since.   May 23, / Rotary Cutter Gearbox...What to use? #8  

rdbrumfield

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Western Washington

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JD 4X4

I run a bush hog, 6ft, and it calls for 90wt. Lost the lower seal many years ago, replaced it and filled with a good grease. I put some 90 in with it and drilled a small hole in the filler plug to vent. Haven't had a problem with it, and I use it regularly, and hasn't leaked since.   May 28, / Rotary Cutter Gearbox...What to use? #9  

coffeeman

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My mower manual asks me to check oil each day before using. I guess it makes sense. However, there is no dipstick on gear box and I would have to remove plug on side each day to check oil. I have a Woods 990-3. A pain in the rear but .... oil is cheaper than bearings and gears. Does anyone know an easier way to check oil; maybe I could add a dipstick?

Cheers....Coffeeman

tater pop

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Jan 13,

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6

Maud texas usa

• #1

I'm in line to get a new cutter. I have a mx- tractor I will be mostly cutting grass some a little hard to cut(watergrass) . looking at getting a 6FT rotary cutter . Does the higher HP mean slower RPMs I will not be clearing land with it.I just need something thats makes a clean cut.

gpreuss

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Equipment LDT w/FEL, K650 Backhoe, 5' Rotary, 40" Howard Rotavator, 6' Rhino blade

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Spokane, WA

• #2

Mostly the higher horsepower comes from more torque, although with the MX you have to run rpm to get 540 at the PTO. The mowers are all made for 540 rpm, and cut best at that speed. If you slow them down too much you no longer get a clean cut.

TripleR

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Equipment BX, BX, L HSTC, MHDC and some other tractors and equipment

Sep 16,

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38

SE Missouri

• #3

Not necessarily, check the Land Pride web site and it will give you blade tip speeds etc. and some high HP mowers are essentially the same as lower HP models. I haven't check other makes, but don't know why they would be different.

I use an RCR and it works well in grass as well as brush. Lots of definitions of water grass, so I'm not sure what you have.

Bulldog

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Rocky Face, Georgia

• #4

Like TripleR said, the blade tip speed is what you need to look at. For example, my Bushhog is 16,345 fpm and it has a very high quality cut. If you want a good cut for grass I wouldn't even look at anything under 15K fpm.

tater pop

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Jan 13,

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Maud texas usa

• #5

Thanks for your answers, the reason I ask the question is years ago I had an older bushHog brand bush hog with the old big gearbox that thing would clear a thicket but did not make a good cut on pasture grass. My neighbor had a ford cutter with a small gearbox that would make a better cut in grass at a faster speed than I could run .