Still baffled--water getting in gearbox

aaluck

Well-known member

Equipment
L4400HST, Bush Hog 276, RDTH60, Speeco PHD, etc
Oct 9, 2019
946
771
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Snowdoun, AL
I have been working on this for over a year now and still cannot understand what is going on.....

I have a 12+ year old bush hog 286 that runs like a top, for now. The problem I have is water is somehow getting into the gear box (or rats are playing a trick on me and adding oil in the night). I thought the problem was that I stored it in the elements but now it is stored under a pole barn and the problem persists. I had the pole barn completed in May, 2020. When the barn was complete I sucked out all of the oil I could. I realize that I probably did not get it all but at least most. I then carefully filled the gearbox to the check plug. Just enough so that a tiny trickle of oil was leaving the check plug and sealed it all up with plumbers tape on the fill hole and check plug.

So yesterday I decided to check the oil level. Unit was cold--hadn't been used in a couple of days. I pulled the check plug and oil began to run out. Not a little trickle as I had filled it up, but a good bit and the color was milky. (And, yes, the unit was in the exact same spot where I filled it up earlier--so being level or not level is not an issue here). I cannot, for the life of me, understand how the gearbox is adding that much fluid/water. I realize that during use the oil will thin and get frothy but in this case the unit was cold and should have returned to the level in which I filled it.

Does anyone have any ideas on what is going on? I understand that an over filled gearbox can be just as bad as a near empty one and I don't want to damage any seals. Finally, there is no visible damage to any gaskets, etc.
 

RCW

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Equipment
BX2360, FEL, MMM, BX2750D snowblower. 1953 Minneapolis Moline ZAU
Apr 28, 2013
9,142
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Chenango County, NY
Your gearbox is vented. Daily warming/cooling introducing humidity into the box, then it condenses?

Would be similar scenario to a vented fuel tank introducing water.

Just a guess. Don't know quantity of water you pulled out of it.
 
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aaluck

Well-known member

Equipment
L4400HST, Bush Hog 276, RDTH60, Speeco PHD, etc
Oct 9, 2019
946
771
93
Snowdoun, AL
Your gearbox is vented. Daily warming/cooling introducing humidity into the box, then it condenses?

Would be similar scenario to a vented fuel tank introducing water.

Just a guess. Don't know quantity of water you pulled out of it.
So...do I just keep running it? Should I drain it to the check plug before use? Am I thinking about this too much?
 

bx tractorjoe

Active member

Equipment
kubota l2501 upgraded from a bx23s john deere 670 husquarvana huv 4421 gxp
Jun 3, 2020
258
140
43
loxahatchee flordia
Your vent is bad.. usually they have a one way valve to allow pressure out, but not let anything in, like a pcv valve for older car engines.. yours must be open all the time.. only one way for moisture to get in the gearbox so pull your vent and see what it is
 
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aaluck

Well-known member

Equipment
L4400HST, Bush Hog 276, RDTH60, Speeco PHD, etc
Oct 9, 2019
946
771
93
Snowdoun, AL
Your vent is bad.. usually they have a one way valve to allow pressure out, but not let anything in, like a pcv valve for older car engines.. yours must be open all the time.. only one way for moisture to get in the gearbox so pull your vent and see what it is
I just ordered a new one. Hopefully you, sir, are correct. Thanks
 

RCW

Well-known member
Lifetime Member

Equipment
BX2360, FEL, MMM, BX2750D snowblower. 1953 Minneapolis Moline ZAU
Apr 28, 2013
9,142
5,213
113
Chenango County, NY
Huh - didn't realize they were one way....learn something new everyday.

Certainly does makes sense.

Probably same idea for gearboxes on my MMM and snowblower auger drive?

Hope bx tractorjoe is right and that fixes it!
 

bx tractorjoe

Active member

Equipment
kubota l2501 upgraded from a bx23s john deere 670 husquarvana huv 4421 gxp
Jun 3, 2020
258
140
43
loxahatchee flordia
When my 60 inch land pride finish mower was delivered still in the crate, I asked for it like this.. i had to install a vent on top of my gearbox..

Before installing it.. i cleaned it and blew air through it, in the part that went inside. but it would not let air come in, was hard to blow through it too..

Alot of times when a engine has weird oil leaks its because the pvc valve, or crank case vent has clogged or etc.. and the oil will eventually find a way out, and it will run poorly and hot
 
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