If I get time I'll look in Gibbard's book for the page reference where it defines TW... It's NOT Today's World.
All ag chassis tractors were refered to as Front Wheel Assist or MFWD in Ford's case and the term FWD or Four Wheel Drive is universally reserved for full time, equal wheel four wheel drives most often in an articulated chassis. In Ford's case they were always articulated... Hence the 8000 series deriviatives through the TW and large frame 30 series were all refered to as being a 2WD chassis that may or may not have been equipped with MFWD. FW... was the steiger built four wheelers.