Whats up with this gear oil?

[skylarkguy]

So I have a Mitsubishi 372D. Today while running my brush hog it started spewing the gear oil (80w90) out of the boot around the shifter. It was under a lot of pressure and I probably lost several quarts before making it back to the barn. The night before i had topped it off so the level was full.

Someone suggested that there might be water in the oil causing this problem. I'm not sure how water would cause this condition but thought I would pull some out to take a look. I drained a bit of fluid out of the case and found this.

The nasty brown stuff is on the left, with some fresh oil on the right for comparison. There is only about 40 hrs on this oil, although it sat all winter, under cover.

Is something coming apart in my gear case? there is a bit of metallic material in the goo but not much more than I would expect. The filter has a bit of particulate matter but isn't clogged.

So any thoughts on what would cause this? Should I clean out the case with Diesel or Kerosene (or something else)before refilling?

 

[sweep]

I recently changed my hydraulic/gear oil on my TC45A with 186 hours. I was also surpised how nasty it looked with just that many few hours. I also noticed a very, very slight silver sheen near the bottom of the container when pouring it out but my NH mechanic said this is normal.

Your tractor even though covered might be getting water from normal condensation. Do you have a dipstick to check the oil level or a plug on the side of the case? When you said you topped it off, these cases are not supposed to be full to the top of the case.

I also recently changed the oil in the gearbox of my brushog with probably 140 hours on it and it was nasty as well with that slight silver sheen.

 

[Soundguy]

yep.. looks like water emulsion to me.

water will fall tot he bottom of the sump, displacing the oil upwards.

thus if a sump was at the correct level of oil, then had 'x' amount of water added.. it would be overfull.

oil on most metal surfaces is hygroscopic, and will attrat water. in a vented sump that gets hot and cools.. that invites condensation for the atmosphere.. that or you had a leaky boot somewhere.

i'd add a quart of diesel, a quart of atf, and 2 pints of 91% rubbing alcohol, run the machine for a couple minutes to mix well, then drain.. then refill with fresh oil. you will get the bulk of the water out that way. way more than just a drain and refill.

the alcohol is a polar solvent and will 'disolve' the water and carry it out in soloution with the diesel thinned oil, vs suspension or meulsion like it is/was now.

the diesel is a good solvent to thin the oil and get it moving.. help it splash and wash down surfaces. the atf is full of detergents to suspend anything that isn't solvated, and also adds good temporary lube while doing this flush.

this is my standard flush when I fina a machine or implement with a dirty or wet sump.

soundguy

 

[skylarkguy]

Thanks Soundguy...some of this sounds familiar, as chemistry class was a long time ago.

My local Mitsu guys suggested 2 gallons of straight diesel, but your recipe sounds good. He also informed me that I should be running Universal tractor fluid or something similar (30w trans/hydro fluid). My manual had me put the 80w gear oil in it.

Sweep, by topping off I didn't mean the case was full, but I was still likely overfilled anyway. I was just eyballing it through the filler plug, but I did find it has a plug on the side of the case...which gives the correct level. Everyday that I learn something new is a good day I guess.

Thanks

 

[Soundguy]

yep.. alcohol / diesel mix will grab water way better than just diesel.. which will only get it in suspension or emulsification at best.

with the alcohol, it will be carried disolved into soloution. and the alcohol will mix with the diesel, and the diesel will think the atf and any remaing oil in the sump, and if there is any sticky cluimping emulsified oil globs in there, between the alcohol and diesel, and detergetns they should lift and get carried out when you drain the flush.

as for what your machine takes.. that's between you and the owners manual.

if it's a trans only sump.. gear oil is -PROBABLY- fine.. if it's a common shared sump.. I'd for sure use UTF.

heck, even in a trans only sump, you could probably use utf. it's a multi purpose fluid..

soundguy

 

[284 International]

....i'd add a quart of diesel, a quart of atf, and 2 pints of 91% rubbing alcohol...

the alcohol is a polar solvent and will 'disolve' the water and carry it out in soloution with the diesel thinned oil, vs suspension or meulsion like it is/was now.

the diesel is a good solvent to thin the oil and get it moving.. help it splash and wash down surfaces. the atf is full of detergents to suspend anything that isn't solvated, and also adds good temporary lube while doing this flush.

soundguy

This is an excellent post and a great example of a way to practically use chemistry in real life.

I've used acetone in similar ways, but it's possible some rubber seals may damaged by acetone.

 

[Stradbash]

This is an excellent post and a great example of a way to practically use chemistry in real life.

I've used acetone in similar ways, but it's possible some rubber seals may damaged by acetone.

Agreed! Thanks Soundguy. I the only thing I would do differently is to use "denatured" alcohol. If it's reasonably fresh and was not sitting with it's cap loose (as seems to be the case at my hardware store) it should have a lower water content than the "rubbing" variety. I would also leave the gearbox open for a while to let the remaining alcohol evaporate and maybe even warm it up a bit (carefully!) if it was humid or cool outside. Pretty minor points...
I use alcohol all the time after cleaning machine parts in an ultrasonic cleaner to help remove/dilute the rinse water asap.
Yes, acetone -might- damage the seals and also paint.

 

[Toyboy]

Something that wasn't mentioned. With water in the oil when it gets hot it will expand. That could be another reason you were blowing it out.

 

[Soundguy]

Agreed! Thanks Soundguy. I the only thing I would do differently is to use "denatured" alcohol. If it's reasonably fresh and was not sitting with it's cap loose (as seems to be the case at my hardware store) it should have a lower water content than the "rubbing" variety. I would also leave the gearbox open for a while to let the remaining alcohol evaporate and maybe even warm it up a bit (carefully!) if it was humid or cool outside. Pretty minor points...
I use alcohol all the time after cleaning machine parts in an ultrasonic cleaner to help remove/dilute the rinse water asap.
Yes, acetone -might- damage the seals and also paint.

sure.. denat will work.. just harder to find for some people. the average joe can hit a walmart or walgreens, grab the 91% stuff, and the cheap atf fromt he auto section.. same at a jiffy store.. in fact.. diesel, cheap atf, and alcohol could be 1-stop shopping at most jiffy store / gas stations.


and ditto on the acetone.. too many chances for seal damage IMHO

soundguy

 

[dodge man]

Does anybody think the "fresh oil" on the right in the pictures looks funny? It looks like it has globs of stuff in it. It doesn't look right to me.