Thanks Lang, that is interesting.
That seems to confirm that, thus far, MH were the 'original' users of the term 'All Wheel Drive' on both their placarding on the scuttle of Fords equipped with the MH drive system, and in their handbooks and technical data. Attached is an MH technical manual which is dated January 1939, and uses the term both on the front cover and throughout the text.
This website seems to provide a reasonable differentiation between the two systems in terms of current usage, but on reading the MH manual, it seems they (ie MH) used it in a different sense: a conventional system which would cover both their 4x4 and 6x6 applications.
https://www.digitaltrends.com/cars/w...l-wheel-drive/
Mike