I have never read up on the various differential gear ratios in the 123s, so reading this string is interesting. I have a simple question....

In my previous 85 300DT (sedan), I could get highway mileage of 30 mpg as long as I kept speed between 60 and 65 mph. In my current 84 300TD (wagon), I can only get 25 mpg. I realize these are two different cars, and various differences may play a role (one car may have better injector spray pattern, better compression, etc.). But if we assume all other factors being equal, is the lower fuel economy in the wagon due to different gear ratios? E.g. is the wagon geared lower because the car is designed to haul heavy loads?

Thanks,

Mark

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1984 300TD Wagon, 407,800 mi (current daily driver)
1985 300DT Sedan, 330,000 mi (gone to that great autobahn in the sky)