So the light weight, temp stable and BLUE hydro fluid I use in my plow pump would be a good choice? BTW The bright blue color is for IDing problems when we rip off plow or tranny lines from downed tree branches when plowing. Should make a good mess in the bilge! lol Gary
JMO......but I've ran ATF in the Oildyne system for over 30 years with no problems and I've also never noticed any difference in lift rate between 60 and 100 degrees.
Actually the thicker the oil, the more the working pressure but the slower the oil moves because of it's being thicker!
Not saying the lift rate won't change with High Vis vs. Low Vis but the High Vis will have more pressure.
There is a trade off point with thick vs thin and many times I put a couple'a oz's of 50 weight in the system, along wit the ATF just to raise the pressure a tad!!!
It's similar to putting that STP Honey in yer engine to raise the oil pressure before ya' sell-it!!!!
OR even better;
I have seen HUNDREDS of Transmissions that would run WAY past time to change the fluid and the ATF had gradually thickened through the years from contaminants and old age, which would keep the tranny going! Change the fluid and it wouldn't even move the ride!!!!
Several times I've had a customer drain the fresh and put in 50 weight just to get it back up in their driveway....OR into my shop!!!
Again, JMO.....but you won't find me racing around looking for any other hydraulic oil when ATF is so handy!!!
ALSO FYI:
Lake Water can be used in a pinch to get you back on the trailer if you ever happen to be in the boonies and find yerself too low on fluid to operate!
It also works in your hydraulic steering system.......just Be Sure to drain and purge all the Pink Foamy Stuff ASAP or when you get back home!!!!