Thought this link to Spielbergers book might be intersting
Militarfahrzeuge - German Softskinned Vehicles of WW2
Prior to 1943, Germany was producing roughly 50000 trucks of various kinds per year. According to the USSBS the Germans were seriously underutilizing their limited capacity to produce MT. Quite a number of factories were hived off to produce other things, like aircraft components and bits for tanks. Not all of these vehicles could be sent to the military, about 15000 vehicles per year were needed for civilian purposes, and another 9000 were needed for use by foreign nations. That left around 25000 vehicles per year for entry into the German Armed forces. However, up until June 1941 attrition from the heers (Im not even looking at the other services) ran at about 5000 vehicles lost per month, and of these a consistent 80% were written off for noncombat reasons....they simply wore out, crashed, etc.
Up until Barbarossa , the Heer managed to maintain its mobility by some very desperate measures. They acquired a lot of captured vehicles in France and other parts of Europe (including many vehicles from the BEF, left behind on the Dunkirk Beaches) and received about 40000 trucks of foreign manufacture (mostly French types). Over 100000 civilian vehicles were commandeered for the Army. This allowed the army to enter russia with more or less a ful complement of vehicles, though the quality of the park was patchy. The Germans entered Russia with about 600000 vehicles
Thereafter the rot set in..... attrition rates increased by approximately 2.5 times, to roughly 12000 vehicles per month. There were no other expedients that the Germans could draw on, and in the critical years of 1942 and 1943, German truck production remained around the 50000 mark. From memory production in 1942 ran at about 48000 units, whilst in 1943 production increased to 52000 units. This was nowhere near enough to meet all demands, and as germany started to suffer defeats in the field, her losses in trucks shot up alarmingly. In the first four months of 1944, German truck losses amounted to 109000 vehicles. They produced 111000 trucks for the whole of 1944. The army reached a peak strength of 9.5 million men in mid 1943, but the numbers of divisions just kept exploding. These losses, inadequate production, and explosion of numbers, crushed the mobility issue for the Germans. Adding to all these problems was a relatively low servicieability rate....brought about by the multiplicity of types and their relative fragility
Two things needed to be done to address this. The Germans needed to utilize their full automotive capacity. According to the USSBS actual production never exceeded about 70% of productive capacity. The Germans had to stop wasting their money building Tiger Panther tanks, and put up with amore modest AFV program, so that their Infantry could retain mobility. They also had to adopt a rationalization program 2-3 years beforeee they did, and settle on simplified, sturdy types, much as the Russians had done. If they had done that, attrition rates would have been lower and servicieability ratews increased.
Individually, ther were some quite good types designed in Germany, but there were never enough, and too little central contraol and planning put into the production system. The German auto industry was allowed to run with far too much autonomy to be considered efficient
There are a lot of good comments about this issue in Halders Diary as well. He was a good staff officer, if a little conservative, and he knew the poor condition of the German MT arm, and how badly it was rupturing.