44 hydraulic oil

Team, What oil should I run in the 44 unit on my D2 5U12142? When I rebuilt it I filled it with Hydraulic oil but I've seen on a thread here where 10 weight is what Cat recommends. Which is the preferred oil?
Thanks
Dennie

Here are the original specs.
Either engine oil or hydraulic oil is acceptable.

10w oil is equivalent to an ISO 32 hydraulic oil @ 155 ssu.

That being said in my Calif climate and well worn pump I run an ISO 68 hydraulic oil (SAE 20 equiv) @ 325 ssu. It is a little slow to build pressure on cold start up.

I would prefer to run an ISO 46 (SAE 10 equiv)@ 215 ssu but it is not compatible with other systems I run off the pump

OM, thanks for the info, while it gets to -25F here I don't intend to go out into it with my D2. I may be nuts but I'm not crazy. All kidding aside I'll stick with the 10 weight and or hydraulic oil, during the winter months I have the old girl inside in my semiheated shop so if for some reason (pull the log truck out?) I had to take her out she'd be warm anyway.
I'll be tackling that right hand steering clutch this winter as soon as the construction projects slow down

Thanks again😆
Dennie