Originally Posted by fixnair
I do it all the time in my 02 F350. #32 mostly but a lot of ATF also. I usually run straight oil. I don't blend it but you can if you want. I've even used synthetic hydraulic oil with no noticable drivability problems other than the exhaust smells like an old bus.
Do you heat the oil? I can probably get some hydraulic fluid from work as well. Would that need to be heated as well?