Hydraulic Fluid vs ATF Oil

[rmaynard 15,461]

Several years ago, I purchased a 5 gallon bucket of Sincopec L-HM 32 hydraulic oil to flush and refill a log splitter. I have half a bucket left. Can this be used in a Dexron III or Type A application (Sundstrand in 875)?

[WHX?? 48,815]

I don't think I would mix the two. It would be OK if the 875 were flushed if it has atf in it now.  If not mistaken the 32 oil is brown in color. The 32 is reference to the viscosity of the fluid. 

32 would mix ok with other numbered or "universal" oils. Even non synthetic motor oils in a farmer pinch.  

If your sunny has atf in it now I would stick with that. 

Sinopec has some excellent info.

https://buysinopec.com/blogs/news/iso-32-46-68-100-hydraulic-oil-temperature-range-hydraulic-oil-specification-chart#:~:text=ISO 46 Hydraulic Oil – ISO,working under high-pressure etc.&text=ISO 68 Hydraulic Oil – ISO,a large load-carrying ability.

[rmaynard 15,461]

This stuff is clear.

The 875 went from Type A to Wolfs Head full synthetic, back to universal ATF (red). I should have never drained the A. I'm good on level ground, but lose speed going up hill.1

[Pullstart 62,885]

I have asked the question recently if there is a reason why not to mix the two.  It’s pretty much stated that if it started with one, never switch to the other.  My plow trucks have blown more lines than I can count.  I pretty much have grabbed hydraulic oil, tractor trans oil, plow fluid, etc.  Lifting 8’ front blades, 16’ rear swing wing blades, 9’2” v plows, you name it I’ve run it.  Yes, probably motor oil to get me home.  I’ve never torn up a pump, I’ve never found myself without pressure.

 

Now, on a GT, I’ve never been stranded miles from home, so I’ve always kept to like fluids.  But I still raise the question.  Can anyone explain th downfall of mixing?  My auto shop teacher explained to me in school that ATF is a miracle worker detergent, better than any injector cleaner, better than any engine flush additive.  I’ve dumped countess quarts of ATF into my gas or diesel tanks, my engine oil a week before an oil change, etc.  I’ve never seen a drop in oil pressure.  I’ve never found out damage from it. 

[squonk 41,118]

Tight honkin tolerances in a hydro trans. Plus high temps and loads. Different oils may also separate when sitting. I could see your out plowing snow in a storm and blowing a hose and putting in whatever you can get, but why would you even consider changing the fluid from one to another on a GT. Cost isn't much  different. I use Mobil 1 for cold flow and high heat shear resistance.

Edited April 29 by squonk

[953 nut 55,232]

1 hour ago, Pullstart said:

 I’ve dumped countess quarts of ATF into my gas or diesel tanks, my engine oil a week before an oil change, etc.

When I was in highschool our auto shop teacher gave the same advise. He said it was a very high detergent 10 W oil.

I bought a '52 Buick that had been sitting unused for a few years and the lifters clattered quite a bit. A quart of ATF, a ten mile drive and an oil change cured the problem.

[rmaynard 15,461]

Legitimate question Kevin. It's not like mixing oil and water. They are both hydraulic fluids. My problem is that the previous owner had never changed the fluid since he could never find the drain plug. So he just added the original "A" fluid as needed and it was still working great when I got it. My maintenance oriented mind said 'change the engine oil, change the transmission fluid, put a new filter on'. However, other then the one quart of "A" type fluid that came along with the tractor, I could not find anymore. For that reason I decided to use a full synthetic. Very disappointed with the results. A year later, I drained the synthetic and replaced with Universal ATF fluid. Not much better. I asked "what could it hurt to try the Sincopec?

[953 nut 55,232]

Mike @squonk has said he used 10 W 40 on a Sundstrand and had a stronger transmission as a result.

[squonk 41,118]

40 minutes ago, 953 nut said:

Mike @squonk has said he used 10 W 40 on a Sundstrand and had a stronger transmission as a result.

Yup 10-W40 Mobil 1 

 

I put a temperature probe on my hydraulic lift valve and on a hot day temps got close to 130° 

Edited April 29 by squonk

[rmaynard 15,461]

Okay, here's the results. I drained the tranny, drained the filter. I put in 4 quarts of Sinopec L-HM 32 hydraulic fluid, checked the dipstick, put it in forward and off I go. First trip was up the hill that always bogged me down in the past. No problem. Then it was the push test. I put the front wheels against the snow plow on my 416-H. I pushed it uphill until I hit gravel and the wheels spun.

So far, so good. I'm going to pull the aerator with about 200 pounds of added weight and check the temperature later today.

[Wayne0 457]

11 hours ago, Pullstart said:

I have asked the question recently if there is a reason why not to mix the two.  It’s pretty much stated that if it started with one, never switch to the other.  My plow trucks have blown more lines than I can count.  I pretty much have grabbed hydraulic oil, tractor trans oil, plow fluid, etc.  Lifting 8’ front blades, 16’ rear swing wing blades, 9’2” v plows, you name it I’ve run it.  Yes, probably motor oil to get me home.  I’ve never torn up a pump, I’ve never found myself without pressure.

 

Now, on a GT, I’ve never been stranded miles from home, so I’ve always kept to like fluids.  But I still raise the question.  Can anyone explain th downfall of mixing?  My auto shop teacher explained to me in school that ATF is a miracle worker detergent, better than any injector cleaner, better than any engine flush additive.  I’ve dumped countess quarts of ATF into my gas or diesel tanks, my engine oil a week before an oil change, etc.  I’ve never seen a drop in oil pressure.  I’ve never found out damage from it. 

OT, but in my younger ( stupid years,) I went off road in my '73 Jeep Wagoner.

Went down a steep hill of rock steps. At the bottom was a stream with a snowmobile bridge across it.

Dropped one wheel off the side of the bridge and got hung up on the spring. Boiled the (auto)  tranny dry trying to get it off.

Buddy found a downed tree for a leaver and we got backed up.  Truck would not move after that. Had a can of 30w under the seat so I said "WTF, let's put it in"

We got 3 miles out of the woods on that.

Oil is oil.