Hydraulic Fluid - Confused?

RustyBoy

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I'm confused about something and maybe someone could clarify. The Hydro-Gear trans uses hydraulic fluid yet the manual states to use 20-40 motor oil. Having two cars that have used hydraulic fluid, I know there is a distinct difference between the two. Further, Gravely sells a synthetic hydraulic fluid in 15w50 and 20w50. Any thoughts????
 

Mike88se

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I'm confused about something and maybe someone could clarify. The Hydro-Gear trans uses hydraulic fluid yet the manual states to use 20-40 motor oil. Having two cars that have used hydraulic fluid, I know there is a distinct difference between the two. Further, Gravely sells a synthetic hydraulic fluid in 15w50 and 20w50. Any thoughts????
Yes... follow the manual ;) My Gravely manual says to use Mobil1 15w50 oil. Hydraulic fluid isn't necessarily what you think it is. It's a generic term.
Hydraulic fluid - Wikipedia, the free encyclopedia
 

KennyV

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Like Mike said.... Is not always going to be what you may expect. Hydraulic fluid in some systems can be water.
Depends on what the system is designed to do & utilize.
A good multi-viscosity synthetic Motor Oil is the best "fluid" to run in almost every hydraulic mower. :smile:KennyV
 

RustyBoy

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Yes... follow the manual ;) My Gravely manual says to use Mobil1 15w50 oil. Hydraulic fluid isn't necessarily what you think it is. It's a generic term.
Hydraulic fluid - Wikipedia, the free encyclopedia

Ok, if I follow my manual, which I will, states "Use 20W-50 engine oil with an SL API classification." Unlike your manual, my manual isn't brand specific for the oil nor does it mention synthetic. Lastly, even more confusing, there is a "Warning" for hydraulic fluid while there isn't a warning for motor oil, so the manual in this regard is making a distinction between hydraulic fluid and motor oil. However, I prefer synthetic versus conventional oil.
 

Natureboy

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As said, use the 20W-50 motor oil. The SL rating will be on the oil container listing it as so. As far as brand of oil-ANY 20W-50 rated by API as SL will be acceptable. Don't over think it.
 

djdicetn

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Ok, if I follow my manual, which I will, states "Use 20W-50 engine oil with an SL API classification." Unlike your manual, my manual isn't brand specific for the oil nor does it mention synthetic. Lastly, even more confusing, there is a "Warning" for hydraulic fluid while there isn't a warning for motor oil, so the manual in this regard is making a distinction between hydraulic fluid and motor oil. However, I prefer synthetic versus conventional oil.

The advice you are getting about following the recommendation in your owner's manual is spot on!!!

My Gravely manual(and I checked the Hydro-Gear website to confirm) states conventional 20W-50 oil. I am not going to get into a debate with any users(no offense intended:0) that believe synthetic oil is the greatest thing since sliced bread but I did go to Advance Auto Parts and got a quart of Pennzoil 20W-50 to keep my reservoirs topped up. And that is what I will use in the trannies whenever the fluid/filter service is performed. When I do my 75 hour fluid/filter change I will probably stock up on Pennzoil 20W-50 to take care of the next several services. You will find that since almost all new cars since the early 2000's are leaning towards the lighter weight 5W-30 oils(for obvious emission standards), this has made the formerly popular heavier weight oils harder to find(I used Castrol 20W-40 in my MG's for years...I owned 4 different ones). I am now an avid Pennzoil user on everything I own and with a 1995 Z71 Chevrolet Silverado with 239,000 miles on the original 350 V8 that still runs like new I can attest to how well it protects engines(I have used Pennzoil 10W30 since I drove that truck off the dealer's lot in 1995). Of course, the oil brand is of little importance, if it a well-known brand, but you need to use the 20W-50 oil as recommended. That's my story and I'm sticking to it:0)
 

djdicetn

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As said, use the 20W-50 motor oil. The SL rating will be on the oil container listing it as so. As far as brand of oil-ANY 20W-50 rated by API as SL will be acceptable. Don't over think it.

Yep, all former and current API rating oils are "compatible" on multi-viscosity engine oils.
 

coder

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The primary recommended lubricant is Gravely / Ariens 00057100 15W50 hydro fluid, which
is "fully synthetic". So a synthetic based product is not necessarily a bad thing.

Interestingly several Ariens manuals do mention that this fluid (prod. # 00057100)
is actually the Mobil-1 15w50 synthetic (probably the "extended performance" since they mention this is a high TBN product.
The TBN refers to the level of alkaline acid neutralizers. The ZDDP content of the Mobile-1 15w50 is 1200ppm.
Could be a bit higher, but not bad.

So it looks like you don't have to pay fifteen bucks a quart for the rebadget Gravely fluid, you can pick up
the mobil-1 at wallymart for around $22 bucks for the 5 quart jug. BTW mobil has a $15 rebate going right now on this oil.
 

deckeda

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Google brought me here ... as far as I'm aware only Gravely refers to motor oil as hydraulic fluid. Look for 15W50 (in my case that's what the owner's manual specs) and what you find "motor" oil for sale.

My interpretation is that it's a lube when used in an engine, or a power conveyance when used under higher pressure to turn wheels.

They could have added a helpful sentence for clarity since you won't find "15W50 hydraulic oil" for sale unless it's in a red Gravely container that costs twice what Mobil 1 does.

Best analogy I can think of is something like 303 tractor fluid oil. It could be a transmission lube, but it also raises the front blade (for example).

"Honey, the tractor needs more fluid oil."

"Oh, so that's different than solid oil?" LOL
 

StarTech

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That like buying organic chicken vs non organic.. What is the non organic made out of, rocks or some other non organic material?
 
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