75ish owatonna 440 skid steer hydraulic fluid type???

[leroyd92]

I'm not super familiar with hydraulic Fluid and the types or differences.

My 75ish owatonna skid steer has ATF in the hydraulic system " per the previous owner " he claims that's what it takes.

I want to replace the filters in the near future and do a fluid change. I don't have a manual yet so this is why I'm asking here.

If I need to use ATF, is there an advantage in using hydraulic fluids? I can get aw32 aw46 and universal tractor fluid all for pretty cheap at my work, I'd have to go to tractor supply for ATF as I don't get much break on it. I want whatever is hypothetically best for the machine, I just don't know what advantages there is. I also don't know if there's better technology's from then or if there's a specific reason why they say ATF.

My skid steer uses 2 hydraulic pumps to turn chains that turn the wheels. I have one main pump that hooks to the smaller ones. The chains go through an oil bath at the bottom " assumingly "

Thank you everyone. I hope to get my manuals soon

 

[DriveHard]

I'm not sure I understand your description of "I have one main pump that hooks to the smaller ones. The chains go through an oil bath at the bottom " assumingly ""

I only know of one skid steer that uses a single open circuit pump with valves to accomplish the propel function, and it is a prototype my company developed.

Using ATF, especially in older hydraulic equipment can speed up yellow metal corrosion that is used in many (all?) axial piston hydraulic pumps. As a hydraulic component manufacturer, we always urge users to use hydraulic fluid, as it is designed for use with the metals in pumps/motors.

Many OEM's will suggest motor oil or ATF for use in their hydraulic system, it is simply due to the fact that it is easier to find, and folks of consumer grade equipment are more comfortable with it.

The only exception I know of is when the same fluid running through your pumps is also used to lubricate a wet clutch...if that is the case, you will need a Universal Tractor Fluid (UTF) that works with wet clutches.

 

[leroyd92]

I have this main pump, and then these 2 drive motors or pumps work the chain drive system

 

[DriveHard]

I have this main pump, and then these 2 drive motors or pumps work the chain drive system

While I don't recognize exactly what you have, it seems to be a traditional setup.

In a traditional Skid Steer Loader (SSL), you will have at a minimum, four pumps and two motors.

You look to have two closed circuit Manual Displacement Control (MDC) pumps that power your two motors that drive your chain cases.
You have one gear pump that should feed into a valve block that controls your work function (bucket functions).
You will have one small gerotor or gear pump that acts as a charge pump for your closed circuit functions.

 

[leroyd92]

The gentleman I got the skid steer from sent me pictures of the pump service manual. Fluid specs say mercon type a. It looks like it give me fluid characteristics of ATF as a guideline

 

[DriveHard]

The gentleman I got the skid steer from sent me pictures of the pump service manual. Fluid specs say mercon type a. It looks like it give me fluid characteristics of ATF as a guideline

If there are no clutches, and living in AZ, I would run ISO 46 or 68 hydraulic oil in the system.

 

[leroyd92]

There's good chance that I'll be using this when it's 90+ outside. Winters are mid 30's in extreme cold cases.

From a little research, aw46 mimics ATF. Is it thicker than ATF? Or have more wear additives?

 

[DriveHard]

There's good chance that I'll be using this when it's 90+ outside. Winters are mid 30's in extreme cold cases.

From a little research, aw46 mimics ATF. Is it thicker than ATF? Or have more wear additives?

HA! Ah yes, those are our pumps... Danfoss Series 18

https://www.precisionfluidpower.com/wp-content/uploads/2019/05/Danfoss-Series-18-Axial-Piston-Pumps-Motors.pdf

I would use the ISO46 and install a temp gauge to make sure you aren't getting too hot in the summer and staying in the visc. specs.

 

[leroyd92]

HA! Ah yes, those are our pumps... Danfoss Series 18

https://www.precisionfluidpower.com/wp-content/uploads/2019/05/Danfoss-Series-18-Axial-Piston-Pumps-Motors.pdf

I would use the ISO46 and install a temp gauge to make sure you aren't getting too hot in the summer and staying in the visc. specs.

Ok. I can easily do this.

Question. What's the reason my 76 manual says ATF and current day says aw46?

It's there any potential issue to avoid switching to aw46?

 

[DriveHard]

Ok. I can easily do this.

Question. What's the reason my 76 manual says ATF and current day says aw46?

It's there any potential issue to avoid switching to aw46?

While Danfoss has never recommended oils, if you talk to one of our engineers, we will always say to use the proper grade (temp/viscosity for your region) of anti-wear hydraulic oil. There are a couple ATF's we actually caution people on using due to yellow metal corrosion.

OEM's will often spec ATF, UTF, or even engine oil to make it easier for their end user. While most applications can survive with this selection, AW hydraulic oil is what we test with, and what is designed for.

If it were my machine, I would have no issue switching to AW hydraulic fluid.

 

[leroyd92]

So maybe owatonna is who spec'd the system to run on ATF ?

I personally don't care what I need to use. I just want to do what's best for all parts of the system. I've been reading that ATF handles heat better than aw fluids and has additives. Yet aw has more of a heat spread and also has additives. Rather confusing



Do you know what a full sized Ssl like this typically holds fluid wise?

 

[leroyd92]

Did you recommend aw46 due to my areas heat temp range? Or because aw46 is similar to ATF that my manual claims to want?