300D Transmission issues

[msaelzer]

Hi,
I bought a 84' European 300D. The transmission was not working, so I went to the junkyard and found one from a turbo model (mine is not turbo). I put that transmission to work, but it seems that there is an issue with the gear ratio. When I drive at 60 mph, it seems the engine is running at very high RPM. Someone told me I should change the differential, and put one that comes from a turbo model. If so, would the car run sluggish since the tranny + differential came from a turbo model?

Thanks,

Max

[olmar]

hi
I just bought a 84 300D turbo. It runs approx. 2800 at 60mph. I am not sure
if this is normal. I would like to see it less. I look forward to reading the response you get.

Tom Wild

Olmar "old mans car" is the name my 84 has been given by my wife.

Yes, 2745 rpm at 62mph is what the '84 300d turbo does. It has a 3.07 ratio in the rear end. The 300d euro, or at least the 300d with the non-turbo made before '82 has a 3.46 ratio, yielding 3090 rpm at 62mph, which could be considered very high rpm for a diesel at cruising speed. The car might be considered sluggish with the higher gear (lower number) however for me this would be a desired trade-off. It should get better mpg on the highway. Also the speedometer will need to be changed if changing rear ends, it will read too slow if the one from the euro is left in. I got this info from the FSM (factory service manual).