Rotary Cutter Gearbox HOT???

[greg_g]

If not already so equipped, a vented fill plug will help the tranny run a few degrees cooler. I've got an extra, if the diameter is right for your fill threads.

//greg//

 

[N80]

I've noticed these types of things before and wondered about them. There should be two types of owner's manuals. One for the basics, one for completely new users who will be nervous about warm gearboxes, etc. I was surprised at one point to feel how hot the tranny/diff on my gear drive tractor was after some hard work one summer afternoon. It worried me until the TBN folks told it was normal.

Just the other day, its was in the 80's and I was mowing some heavy stuff and noticed the gear box on my 6' cutter was quite warm. I could hold my hand on it so I figured it was okay.

But this is the type of thing that new tractor owners are not going to have an intuitive feel for. We might guess a tranny or gearbox might get warm, but how warm? Fortunately, we have TBN and its collective experience/wisdom.

I am going to be changing my gear oil this weekend and since it typically gets into the mid 90's here in summer I think I am also going to go with a thicker gear oil.

 

[agford4x4]

yeah, thats why i asked here. Oddly enough, these boards have more knowledgable people on about specific products than can be found at the manufacturer 99% of the time.

Like i said, i used my folks shredder, but i never hopped off and went to check the gearbox for any reason.

 

[John_Mc]

Most rotary cutters gearboxes run 40-60 degrees above the ambient temperature.

And most people tend to overestimate how hot a piece of metal "feels". At 140 deg F, you will not be able to keep your hand on a piece of steel. This is still well within the safe range of your gearbox.

John Mc

 

[john_bud]

I've noticed these types of things before and wondered about them. There should be two types of owner's manuals. One for the basics, one for completely new users who will be nervous about warm gearboxes, etc. I was surprised at one point to feel how hot the tranny/diff on my gear drive tractor was after some hard work one summer afternoon. It worried me until the TBN folks told it was normal.
.

Too true. One thing I have noticed is that convential wisdom that the more experienced folks have can often be found in product literature from the 50's and 60's. For instance, Ford's product brochure for loaders calls out the usual stuff on time to lift, tilt, dump etc. But, it also calles out pump flow by engine RPM and at a temperature of 160 F. Obviously, if you feel a loader that is working hard and it feels hot to the touch, you may be concerned until you remember the spec called out 160F as the oil temperature where the equipment was measured -- so 160F must be normal.

When was the last time you read a product brochure that had all the technical data you could ask for, cylinder dimensions, pump flows, dyno chart, etc. The marketing branch is getting dumber about the products and the literature is going down with them. (Just my own jaded opinion)

jb

 

[B2400]

You might consider switching to a synthetic gear oil after you get some hours on it. Synthetics seem to run a little cooler. Switched my KK 48" to Mobil 1 85W140 and runs fairly cool.

 

[Rod in Forfar]

I took my laser thermometer to a new Chinese gearbox, a warranty replacement, because it was so noisy. After 50 minutes of mowing 6" grass, it ranged from 132 to 140 degrees F on various parts of the gearbox.

 

[N80]

Old thread! I've got my same JD light duty cutter. Same hot gear box. Still pushes gear oil out the vent valve if it is hot and is run hard. It was well used when I bought it and that was at least six years ago.

It runs fine, makes no noise, no vibration. I just keep the gear oil at the right level and paint over the rust spots!

 

[HayDR]

First check the vent plug. Take it off and blow through it. If you can't blow through it easy, then fix it or replace it. Typically rotary cutter boxes run 40-50 degree above ambient temperature.

 

[greg_g]

Also check the fluid level and quality. It should not be gray and foamy, nor be above the level of the side drain. FWIW, the Chinese RC that I bought some years ago didn't come with a vented fill plug, I had to find and fit one from the aftermarket.

//greg//