Oil Spec for Hydros

[Bill D 1,921]

I was wondering if there was a specific oil specification required for hydros?  All of our engines require an SJ rated oil.  Is there a similar spec for transmission oil in the hydro transmissions? Are the current SP rated oils suitable for use in a 30 year old Eaton or 40 year old Sunstrand hydro that calls for motor oil?   Bill

[Maxwell-8 4,275]

16 minutes ago, Bill D said:

I was wondering if there was a specific oil specification required for hydros?  All of our engines require an SJ rated oil.  Is there a similar spec for transmission oil in the hydro transmissions? Are the current SP rated oils suitable for use in a 30 year old Eaton or 40 year old Sunstrand hydro that calls for motor oil?   Bill

I don't know a lot off what is suitable for the hydro trans. But the rule is, newer oil ratings are better, but still be compatible with the older oils.

I do know we need to use SAE30 or other high zinc oil in flat tappet engines (most small 4stroke engines) as newer motor oils reduced there zinc content and I have seen engines fail because of it.

 

Problems can come up when using new GL5 manual trans oils in older manual trannys that originally used GL1 or GL3. New GL5 will eat up brass and copper on those trannys.

Edited May 13, 2021 by Maxwell-8

[Pullstart 62,881]

I’ve learned that clean oil is better than old oil... any oil is better than no oil... and annual changes are better than quality stuff dated 2016.

 

 

[squonk 41,118]

Newer oils are far superior to the stuff spec'd out when these hydro's were built. I run Mobil 1 10W40 in my 76 piston-piston Sunstrand and Dexron/Mercon in my 65 Hydrogear

[JoeM 7,874]

I have switched over to International Harvester Spec Hytran. It is a 10-30 weight that matches up to the application very nicely. The anti wear additive package is consistent with the gearing and hydraulic needs. 

I actually found this when messing with Cub Cadets and how smooth the hydro transmissions were when using that oil.

 

But overall it is tough to beat success, wheel horse as been specifying 10-30 motor oil for years and there are alot of them still running. 

 

Only brand I stay away from if "LACK-OF" 

 

Pretty much is up to your budget. 

[DougC 2,641]

I'm old and own 2 old 520H tractors. I use 10w30 NAPA motor oil which I am told is Valvoline and I believe it probably is but I always spend the extra money on the wheelhorse/Toro hydro filter. Thats just the way I am..... Every spring after the motor oil and filter change and grease job the hydro gets attention before the first mow. Kinda funny to see my neighbors buying new mowers every 3 years when mine are 25 and 30 years old...

[shallowwatersailor 3,213]

Condensation buildup in the transmissions would be a reason for changing. But if anyone has felt their transmission and transaxle after a good workout, you know how hot they get. That is a reason to keep the fins clean on the transmission and the cooling fan with all of it's blades.

[squonk 41,118]

I replace my oil every year after the Big Show .I only have about 40 hours on it depending on how much snow removal time is on it.

[Maxwell-8 4,275]

But how many quarts do these hydro's take?

[pfrederi 17,739]

Buy at least 5 qts.  If you have completely drained (taken apart) the system and any cylinders it may take a bit more more...If you just drain from the drain plug it will take less than 5, more like 4.5  qts