Late-war US and German OOB questions

[Ratzki]

TD Battalions did not mix vehicle types; they were 100% of their slated vehicle type (M18, M10, or M36).

So even when replacement vehicles were ordered, they would be of the same type? I do not know what the factory run is for each type of vehcle, but would have thought that the newer, more proficient, or more numerous vehicle design would replace reguardless of type. I figured they would not mix in platoons, but would replace whole platoons inside a company.