Funnily enough, I picked up an interesting note at Malvern -
General order no. 860 of 2nd July '43 changes the oil that is to be used in vehicles. Hypoid is for listed applications only.
For B vehicles this is live axles of -
certain Chev vehicles (Wa, KC, KE, C15, WB, KD, C8, C.4152 tipper),
Dodge all models,
Fargo all models,
all American passenger vehicles including jeeps, Lincoln and Zephyr, but excluding all Fords.
Hypoid axles are to be marked with a red bar on the casing. All vehicles that already have the marking but are not on the list are to be painted out. All vehicles that are on the list but have a red cross on a white background painted on the rear axle diff will have the upper and lower portion painted out to present a red bar (evidently an earlier Hypoid marking).
B vehicle engines and gearboxes were not to use Hypoid. The vast majority of vehicles types were not to use Hypoid.