Quote:
Originally Posted by BATComm1966
Not to steal the thread, but have a question... just acquired a 81 240D with the 300TD conversion, runs great 4spd car..also got a replacement diff from the owner which he states are more highway"friendly" gears.
I drove it home about 60 miles and agree a 5th gear or higher gearing in the rear would do it some good.
My question, what gear ratio is stock, he believes this set is 3.32 but I havent got any numbers off of them yet.
Looks to be a pretty straight forward swap.
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The ratio is stamped on the rear of the casing. When changing the rear end you need the speedometer from the same car or from another that has the same rear end ratio. You probably have the original 3.69 ratio in the 240d now. The 3.32 ratio mentioned for some reason does not ring any bells for the five cylinder naturally aspired diesel engines. It still might be right though. Check for the ratio on the casing of the rear end you where given. .I found that even the original rear end ratio for the natural aspired five cylinder engines. Like in my 1977 300d seems not quite low enough. Yet I agree the 3.69 is really inadequate. Even for the four cylinder engine. I live close enough to sea level with no really serious hills. Needs can vary on location topography altitude and climate. Use as well. If you had a turbo engine I would jump to the 2.88 without a second thought.