[ihc] transfer case oil

[<spamaddy@xxxxxxxxxxxxxx>]

Howdy all.  I've got a quick question about the type of oil that should go
in a Dana model 20 transfer case.  The manual calls for "straight mineral
oil SAE-90" but it seems that isn't produced anymore (or available under
that name).  What type of oil do y'all use?  Can a standard 90 weight gear
oil be used?  My Internet research indicates that "straight mineral oil" is
the same as GL-1 gear oil, but I can't find it anywhere (auto parts stores,
farm stores, oil companies).  Is there an online retailer that sells this
stuff, or is there an off-the-shelf replacement?