Adding Hydraulic Oil to Slide

[Locksmith]

I have been noticing my slide on my 2003 Class C Gulfstream is out an inch or two after traveling for a day. I checked the oil reservoir and it is low. I checked with an rv facility and they wanted to know if the oil was colored or clear? The pump has a label that says the motor is a SAE J1171 Marine from Parker Oildyne Div in Minneapolis. The pump and reservoir is a Dewald Ser# 209572 and the oil is light blue and clear. There isn't a dip stick, just a multi-thread fill cap. The label says that a STD Automatic Transmission Fluid will work. The Parker website says to use ATF, OD18 or other clean hydraulic oil with a viscosity of 150 to 300 SUS at 38degrees C (100F) is acceptable if another type of fluid is needed. My motorhome owners owners manual says use 10# hydraulic fluid. The automatic transmission fluids that I looked at don't say anything about being standard or the weights. I'm completely confused. Can anyone enlighten me as to what fluid to use and how much?
Thanks in advance for any info.
Larry V

[JCM]

Buy some HWH oil (for their jacks etc.). It is a transmission oil but has no dye. If it leaks it won't stain as bad.

[Locksmith]

Thanks for the speedy reply. How full should I fill the reservoir? I'm assuming full enough that it doesn't run out when a replace the cap-plug?

[JCM]

There might be a mark on the filler cap. Make sure all slides etc. are retracted before filling. That way you shouldn't overflow.

[Locksmith]

I did as you mentioned and it works great!!!
Thanks
Locksmith