Bushhog Gearbox Oil Foaming

[Creamer]

I ran my 5' Bushhog Squealer mower for about 45 minutes the other day and i noticed oil foaming out of the vent in the gearbox. I had checked the oil before I started and what was on the dipstick looked very clean and no evidence of moisture. I have not changed the oil in this gearbox for probably ten years. thoughts?

 

[Gary Fowler]

If you have not added any oil, it could be condensation (water) in the oil raising the level causing the oil to foam and come out the vent. Its easy enough to change it and put in new 90W gear oil especially when the oil is hot as it will drain better then. I think after 10 years you have gotten your monies worth from that oil anyway.
Just change it and make sure you don't over fill when you do.

 

[gwdixon]

Gary is absolutely correct. Water in the oil regardless of where it came from. Lubrication will be impaired.

Indiana has its share of winter cold, high humidity, pouring rain, and rapid temperature changes. Even if you cover the gearbox, which you should, moisture can work its way in.

I know changing oil in those implements can be a pain but it needs to be done. Depending on use, a couple of years should be the limit under the conditions in your area.

 

[Creamer]

But would water from condensation make it foam? The oil was right int he middle of the range when I checked it prior to use. I am not arguing that it shouldn't be changed - I know I should and will but I am curious as to the cause of the foam. The gearbox was a little warm but certainly not hot or anything what I would expect for a gearbox that was being run at full tilt and working.

 

[Loadstar]

Good chance it's from moisture. You got ten years on it. Change it, see what's in it, maybe even flush it. Put some new oil in it.

 

[brown40]

I would second a bath or two of diesel/HHO/kerosene after you get the contaminated stuff out; may show you a seal that is open too. Run it (don't USE it) briefly to stir things up, dump, repeat, put in clean.

 

[stuckmotor]

When I last used my Woods Cadet around 30 years ago, I used an oil that claimed antifoam properties. It foamed out of the vent hole anyway. I was unaware that water in the oil would cause this. I'm about to take the Cadet out of retirement and I think I'll change the oil first.

 

[greg_g]

As you know, oil and water typically don't mix. Pour them individually into a glass beaker, they'll separate into two distinct layers. However - once vigorously agitated - certain ratios of water to oil will form an emulsion. The "foam" you describe is actually the agitated emulsion. And even after draining, that stuff clings to the inside walls of a transmission. Hence the kerosene flush a very sensible step in replacing the contaminated fluid.

//greg//

 

[LD1]

Ditto on the water contamination.

Drain, Flush, refill. Easy as 1-2-3:thumbsup:

 

[Dave M7040]

Remember, after sitting, the water will be on the bottom of the gearbox and the oil on top so the dipstick will show the oil level as correct but you you have a problem and should change the oil.
Dave M7040