Change the differential and the speedometer to match. instead of a 3.69 diff go to a 300d'S 3.46

6% lower RPM

enough to make a nice difference at higher RPM, eg: 4000rpm becomes 3760rpm

however, it's not too much of a change to make the lower speeds still doable, expecially in a manual

I did get to ride in a car with a manual that the owner swapped the diff, it was a huge improvement.

If I’m forced to take the 240D on the freeway I just don’t go over 60-65MPH. I admit to the occasional sprint to 75-80 MPH (I hit 84 once, yikes!) to get the hell out of somebody’s way, but it’s definitely not good for me.

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1981 240D Four on the floor, Orient Red over Parchment, bought with 154,000 but it's a daily driver and up to 180,000 miles, mostly original paint and all original interior.

Have you done this modification? How does it drive at city speeds?

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Why I will never do business with "DieselKraut" again

http://www.peachparts.com/shopforum/mercedes-benz-used-parts-sale-wanted/378935-why-i-will-never-do-business-dieselkraut-again.html