I have an old Michigan wheel loader that I want to replace the hydraulic fluid while replacing some hoses. Total capacity is 55 gallons. The owners manual says that Dexron can be substituted in cooler weather. I am tending to go with Dex III because I feel that it lubricates better, does not absorb water, and will better inhibit corrosion. As for the cooler weather issue, I will not be using the machine very hard, and I believe that the new Dex III can probably handle heat better then the old Dex of 40 years ago. Does anyone have any opinions on this? I guess that the system will require a flush, but what happens if some of the old fluid gets mixed in with the Dex?
AW 30 vs. Dexron III for hydraulic system
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DieselPower
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Actually AW32 hydraulic oil and Dex III / Mercon have almost the same viscosity SUS @ 100 and 210 deg. F. So as far as viscosity goes they are about the same.
ATF isn't necessarily any better at water/oil demulsibility than hydraulic oil is. You would probably be better off with a high quality hydraulic oil that shows a ASTM D-1401 Demulsibility rating of excellent. Also depending on where you are located and if you plan on operating in very cold temps you may consider a Low Temp hydraulic oil that has a lower pour point than regular hydraulic oil.
If water contamination is a problem you might consider installing a 1 micron bypass filtration system that has a water absorbing filter. It would absorb the water into the filter element and also help you greatly extend the drain intervals.
ATF isn't necessarily any better at water/oil demulsibility than hydraulic oil is. You would probably be better off with a high quality hydraulic oil that shows a ASTM D-1401 Demulsibility rating of excellent. Also depending on where you are located and if you plan on operating in very cold temps you may consider a Low Temp hydraulic oil that has a lower pour point than regular hydraulic oil.
If water contamination is a problem you might consider installing a 1 micron bypass filtration system that has a water absorbing filter. It would absorb the water into the filter element and also help you greatly extend the drain intervals.