. Many older transmissions (including Fords from the 1930s) contain what is called "white metal" which is not compatible with modern GL4/GL5 lubricants (although some say GL4 takes a very long time to do any harm). Use straight 140 weight if you can find it, something in the 75W-140 range if not. . I don't remember if the rearend has any white metal, but 85W-90 is about the right weight. . These recommendations are made without having a good idea of what you actually have (for one, I'm assuming a manual transmission; for another, no limited-slip differential). Find some old Ford datasheets for your units (if you are exceptionally lucky, the ID tags will still be on the trans and rearend, but don't hold your breath) and verify my info.
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Thanks, I put 85w-90 in the rear end and was about to put some in the tranmission when the person working on it says it takes a heavy oil thick like honey. He has a model T and uses the thick oil. So maybe the thick is best. Can't find any specs to verify what was used in the original transmission. Ellsworth
Spirax A? (I don't know but you could poke around the internet or consult the handbook / manual)) L
90 weight gear oil or lube.Just ask for gear lube at a parts dealer, most will have it on hnad