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-   -   Auto tranny shift pattern (https://mercedesforum.com/forum/diesel-discussions-33/auto-tranny-shift-pattern-7407/)

phillaf 10-21-2005 09:01 AM

Auto tranny shift pattern
 
Hi, I'm still getting to know my '93 300D 2.5 Turbo. I've noticed something about the shift pattern I wanted to ask about. When cold and for about the first 30 miles or so, the tranny shifts from 1st to 2nd at about 3300 rpm, then 2nd to third at 2500, then 3rd to 4th at about 3500 rpm. After about 30 miles or so of driving, all shifts occur at a much lower speed, about 2000 rpm. Is this normal, or is something out of adjustment. Shifts seem smooth without flare. Hard to tell how a car is supposed to behave when you didn't have it from new. Also, on the diesel Benz's, does the accelerator have a larger amount of play before increasing engine speed than a typical gasoline car does? I'm getting used to it, but it is quite different than my previous gas cars. Any insight you could give would be greatly appreciated.
Phil
Newbie loving his diesel, even at $3.09/gallon!

phillaf 11-05-2005 10:29 AM

RE: Auto tranny shift pattern
 
Hi, folks. Still trying to puzzle this one out. It seems that warming up the engine has very little to do with the different shifting points I am seeing. First to second and third to fourth seem to come about the same RPM and second to third seems to come at about 1000 RPM less. First to second and third to fourth seem to come at between 3200 and 3500 RPM, but only sometimes. Car actually starts off shifting "normally" (lower shift points) in the a.m., and after driving a while, starts shifting at the higher points. If I stop the car and turn off the engine, then restart it, it starts shifting "normally" again. If I accelerate quickly, it starts to shift at higher points again. If I accelerate slowly, it will eventually begin to shift "normally" again. The shifting at higher RPM's only bothers me because I have to accelerate to 60 or 65 MPH to get out of third gear. This is fine getting up to speed on the interstate, but I'd like to get into fourth gear at a lower speed on secondary roads, mainly for fuel mileage reasons. My question is, is this normal, is something out of adjustment, or am I about to have to buy a new transmission? Just changed the fluid, so I have new ATF in it, level is good, shifts are smooth for the most part. Sorry that the post is so long, but I figure the more information, the easier it might be to sort this out. Thanks in advance for any response.
Phil

Kajtek1 11-05-2005 01:15 PM

RE: Auto tranny shift pattern
 
I believe you have adjusting bar on the top of the engine. It is connected to the accelerator linkage with sliding screw in the center. When you loosen the screw, you can adjust the bar length, changing the shifting rpm. Shortening it suppose to get you lower rpm on the tranny shifting.
3000 + is very high for shift. I remember mine 300 shifting at 1200 from 3 to 4.


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