Amazingly, "total war" concept didn't develop in Germany until Summer of 44, and by then it was way too late.
In Jan 45, the Heer still had 650,000 horses and tack on its TO&E. It was still, mainly a horse-drawn Army in the last months of it's existance, whist the Russians, as you said, motored right into Berlin in Dodge's and Fords, American halftracks, etc.
The Russians & the Americans had secure sources of petroleum. The Germans did not. Hence only the Panzer formations were motorized.