milky transmission/ hydraulic fluid in ym155

[vetiver]

I noticed a milky appearance to the trans/hyd. fluid in my ym155 after using it with a small (6) disc implement to make rows. The transmission started making some noises. After shutting down the engine to investigate, the engine did not want to run for very long. The next day it seemed to run better when unloading from a trailer. One thought I had was that water had contaminated this fluid. Another was that the fluid some how broke down. The fluid had been replaced within a couple of months before this use with Autozone JD 303 compatible. Also the very dirty screen filter had been cleaned. I intend to replace the fluid again before the next use. The fluid leaks some in my garage as seen on the floor. Any thoughts?

 

[MrJimi]

Not good thing, you have water in your oil. Find where its coming in and replace oil and filter, oil lubricates and water corrodes.
Jim

 

[Jagmandave]

If it was still milky the next day, I would concur that it's water contamination, If the milkiness went away overnight, it sounds like cavitation (the introduction of air, much like beating eggwhites into merenge sp?)

So, let us know what you find...........

Is this a powershift or geared trans?

 

[vetiver]

The transmission is geared as far as I know. Today I ran the tractor around the
driveway for about 15 minutes. It seemed to run fine. Before running it I checked the trans/hyd fluid and it appeared like a clear liquid. After running for 15 min it seemed milky again. If it is cavitation what can you do to stop it? Is the cavitation in the hydraulic pump? I didn't hear any unusual noise when running and it did not seem to lose power. The PTO works when the PTO shifter is in the low or high position and the engine is moving forward. The PTO does not run in the intermediate position. All this (with the PTO) is normal I think. I have not yet changed the hydraulic/trans fluid since I had the problems in the field last Sunday 11/12/06.

 

[normde2001]

Most Yanmars have 2 or 3 drain plugs for the hy/tran fluid. Most likely if it has ever been stored out in the weather it has collected water through the shifter boot or other places and not properly drained. Be sure you find and drain all of the plugs.

 

[Jagmandave]

He said the fluid was clear this am, doesn't sound like water contamination to me........

 

[Tom_Veatch]

He said the fluid was clear this am, doesn't sound like water contamination to me........

My ignorance/inexperience coming to the fore; once the oil/water are mixed/emulsified how long might it take for the water to settle out if the mixture were left undisturbed? Sounds like you're saying that it'd take more than overnight, but would it be more than a day, week, month, year, never?

 

[Roonabeck]

My ignorance/inexperience coming to the fore; once the oil/water are mixed/emulsified how long might it take for the water to settle out if the mixture were left undisturbed? Sounds like you're saying that it'd take more than overnight, but would it be more than a day, week, month, year, never?

I read somewhere on this forum that hydraulic fluid generally contains something to allow it to keep some amount of water in suspension. I drained milky fluid from my tractor this spring. I still haven't emptied the bucket, and the color still looks milky to me.

 

[Tom_Veatch]

I read somewhere on this forum that hydraulic fluid generally contains something to allow it to keep some amount of water in suspension. I drained milky fluid from my tractor this spring. I still haven't emptied the bucket, and the color still looks milky to me.

That being the case, I guess the answer to my question is "never", at least for any practical purpose. Thanks!

 

[Dusty]

On my old Minneapolis Moline, I had gotten some water into the reservoir that held the hydraulic fluid. I drained the reservoir tank and added fresh fluid. That fluid immediately became contaminated with the water in the cylinders. I checked with the hydraulic shop and they told me to disconnect all the lines and blow them out. To try to drain as much out of the cylinders as I could and to put a fresh filter into the system. Then refill the system and run it till it was hot. Drain and refill a few more times until I got all the contaminated oil out of the tractor. Once a system gets contaminated to the point that the water becomes homogenized with the oil, it is very difficult to completely remove the contaminated oil. All you can do is to keep diluting it till all traces of the moisture are gone. It is a lot of work, and a lot of oil / expense, but if you don't do it, you will ruin other components of the tractor, like the pump.
Dusty