Which Hydraulic Fluid is Best ?

[Gravely20G]

The hydraulic fluid in our used 1996 Gravely 20G garden tractor is "black" color -- Would it be advisable to use:

1. "synthetic" Dextrom II or III fluid or "standard" Dextron II or III?

 

[Howard]

I would imagine that a garden tractor isn't going to get used in very much sub-freezing temperatures. For that reason I would run a standard or non-synthetic fluid.

 

[ac_tc]

Or THF..

 

[bruce381]

THF is better for a trans/hydraulic/gear box common system if your tractor is only the hydrualic end then use a good AW 32 hydrualic oil.
bruce