[David_Hayward (RIP)]

Tony, I believe you must be right. The exception was possibly with regard to the GM of Canada drivetrains. It seems from McKinnon Industries Limited's own records that the DND approached them in 1940 to design the 4 x 4 system for military vehicles. They prevailed on the vast experience that Pontiac, Michigan plant had with GMC 4 x 4 and 6 x 4 trucks from at least 1931 using proprietary components from Timken-Detroit as well as Chevrolet ones. McKinnons evidently obtained licensses from the States to produce the relevant components in Canada. It seems to have been fortuitous that Marmon-Herrington also used Timken components together with Ford ones.

Other than that as Dr Gregg has said in various publications, the first CMPs had components ordered 'out of a catalogue' and it really was a question of using standard items that were to hand at leats initially for expediency. Of course as time went on it probably became easier to order/tool up for specific components based on large production runs and again sharing of components.