Foamy Gear Oil

During my posts on my trans oil I called it the color of creamed coffee and foamy. A lot of responses said I had water in the gear oil. That didnt seem right to me. It has been my experience that water and oil turn grey, not tan. And I have never known water/oil to foam like it did. It was like air injected.
I found this website that shows exactly what the oil looked like when I drained my SA trans.
You might find it interesting.
Dell
Foaming Oil

I never know about Ol' Bob. Lord knows, he puts a lot of thought and work into his analyses, and some seem spot on and some seem a little sketchy. I've had him bookmarked since the first time I stumbled across his site five or six years ago. His stuff is usually helpful and always interesting.

An antifoaming additive in an oil will cut down on the froth, certainly as it relates to air, but getting rid of water being whipped up is a whole different matter than weakening air bubbles. (Like I said in the earlier post on the subject, I'm no engineer and I don't know if the anti-foaming agent suppresses the formation of bubbles in the first place, or works by affecting the surface-tension properties of the oil to allow any bubbles to burst more easily.) The air bubbles, if they form at all, go off into free air. If the stuff does foam up with air, those bubbles will eventually disappear after the agitation is stopped (the same way Bob's little mini-gear boxes cleared up between his test runs). Water, though, has no such place to go, and will generally stay in suspension with the whipped up oil in a frothy soup like you found. There is a point at which you could have more water than can be suspended with the oil and, once the agitation is stopped, that excess amount is what will settle to the bottom and come out the drain first.

That leads to the suggestion that you'll see in other threads about foamy gear oil (and other threads from folks asking if the seat platform/tranny covers on the bigger tractors should get hot enough to be uncomfortable -- they will if you work them long and hard enough), that a mild case of water can be cured with a few days of good hard work. If you get the oil hot enough with heavy work, small amounts of water will evaporate out of the mix and leave you with clearer oil. Tractors that don't get worked a lot or hard will accumulate water (from condensation or, on some tractors,getting in around the shifter) faster than you can cook it out by working it.

My partner in crime wouldn't allow it, but I've thought of a Bob-like experiment to test that theory. It would involve using her double boiler (so as to avoid setting things on fire) on the kitchen range . I suppose I could use the side burner on my grill so as not to stink up the kitchen. Anyway, I'd have water boiling in the bottom, and in the top I'd have some of that frothy, watery gear oil that I'd have captured. Seems to me that that kind of heat (no hotter than the 200*+ of the free steam in the double boiler should boil/evaporate out the water that is suspended in the oil. Evidence would include a clearing up of the oil and a decrease in volume and weight equal to the amount of water that was boiled out.

While I was working on this trans I drained some oil that had only been in for a day of puttsing around the yard.
It came out foamy and frothy. Now after two days of setting in the bottom of a plastic bucket the foam is all gone and it looks like normal rear end oil.
So it doesn't take much to foam up rear end oil. And it does dissipate on its own.
Dell

Ive never seen that using gear oil, but have when I accidentally used hydraulic oil, and only time I did that was on my Cub. I have seen the problems when water gets in gear oil too.

(quoted from post at 11:51:02 10/31/09)

.............My partner in crime wouldn't allow it, but I've thought of a Bob-like experiment to test that theory. It would involve using her double boiler (so as to avoid setting things on fire) on the kitchen range . I suppose I could use the side burner on my grill so as not to stink up the kitchen. Anyway, I'd have water boiling in the bottom, and in the top I'd have some of that frothy, watery gear oil that I'd have captured. Seems to me that that kind of heat (no hotter than the 200*+ of the free steam in the double boiler should boil/evaporate out the water that is suspended in the oil. Evidence would include a clearing up of the oil and a decrease in volume and weight equal to the amount of water that was boiled out.

Click to expand...

Get yourself an old crock pot or deep fat fryer from a garage sale for a couple of bucks.

That and a candy thermometer to measure the temperature is a handy thing for the shop. It works great for installing press fit bearings. Add some hydraulic oil, set the temperature to about 275 to 300 and let the bearings heat in it. When your ready to install them they usually drop right down in place without having to press them on. With a large enough one it even works on front crank pulleys.

I've seen this in a rear-end on a pick-up, its usually caused by a plugged vent.