Journal (car) oil is light, almost like #10 weight. It needs to be light in order to wick up through the pad and onto the journal.
The proper oil to use is Citgo #9. See here:
http://www.docs.citgo.com/msds_pi/C10076.pdf" onclick="window.open(this.href);return false;
Be sure your pad is saturated and you only want a very small puddle, say a pint, visible in front of the pad when inspecting the boxes. Any more just runs out past the dust seal onto the wheel, and ground. Any less and your pad is dry.
Also use this oil in your traction motor cap bearings and front truck center pin lubricator.
Hope this helps!
54T