1981 300D w123 shift points
 

Hi, Im looking at a 300D (non Turbo) and It shifts at 21-22 mph (1-2) and at 41-42 mph (2-3) is this normal? Also, Could you change how soon it shifts to cruise in 2nd at 30mph?

Actually the car doesn't start off in first gear.....First is only obtained by stomping the peddle down before take off......There is a kick down switch behind the accelerator....if it is working correctly....This should allow you to be able to kick the trans down a gear with out have to manually do it via the shifter.....

As for the points, if you look at the speedo, the shift points are on the gauge....

http://www.thetruthaboutcars.com/wp-...lee-Martin.jpg
First gear up to first dot
Second gear up to second dot
Third gear up to third dot

These are very high revving motors....At times it will sound like you are about ready to take off....

Also approaching 4 decades, these transmissions usually need to see a lot of maintenance....shifter bushings, neutral safety switch, vacuum components, fluid filter change etc to see the auto work like it should...

I believe this model also has the vacuum only controlled transmission, which means if you have a vacuum leak...the trans won't shift right....

Thanks, do these shift points sound right? the car is in almost perfect mechanical condition

Those shift points sound about right if your almost flooring it...It is [I]not/I] normal to be cruising around at 40MPH in 3rd, if that's what you're asking.

I am not sure if the '81 is all vacuum controlled, or if it has a bowden cable to adjust shift points. Could you pop the hood and look at the top of the valve cover to see if there's a cable?
The bowden cable is easily adjusted to allow for earlier shifts. If your transmission is vacuum controlled only, I'm sure someone else here can advise you on how to adjust those.

With 2nd gear start and two observed shifts it sounds like you're going into 4th a little over 40 and 3rd a little over 20. With your 3.46 rear end that sounds about right for just putting around town. With it floored it should shift close to the dots as JJ said. Want to keep it from hitting 4th? Put it in S.

Oh gawd, careful of that....or you'll have ever big asss new diesel truck.....thinking your attempting to race them or compete....ask how I know this :P

It is a good idea to do this though, as it helps to knock off/burn off the carbon deposits on the valves....

These cars love to be driven hard.....though few do it....

I used to have a 1973 220D that started off in second with a drop down full throttle switch, but my 1980 300D has always started off in first gear since it was new.

Richard

You should know better by now good sir!

Those dots on the speedo are the maximum allowed speed in each gear. These are "warning dots" if you like.

See this from the owner's handbook (first paragraph) =>

http://www.pruebas.pieldetoro.net/we...D_300D-045.jpg



Depends on the accelerator position - see below

Indeed - see below

I'm glad it is clear that the vacuum only 722.118 starts in first - mine does too!


In the PDF posted by Dr. Sternschnuppe

There are three types of accelerator position

The first one "leergas" means a little bit of "throttle" (<= bad term for most diesels I know, but sounds better than a little bit of "accelerator" in English!) So this is a bit above idle : almost idle.

The second one "Vollgas" is full "throttle" with out the kick down being engaged

The third one "Ubergas" is the best and most superior type of gas of them all! Pedal to the metal - kick down engaged (brakes are for pussies - die muther ****er die)

Oh yeah shift point data for other transmissions of the same era is posted here =>

DIY W123 Transmission Diagnose and Adjustment 722.xx OM 616-7 - Mercedes-Benz Forum

Appoligizes...Forgot to add that "Max Allowed" :P

Then I also can keep up on who's trans starts in first and who's doesn't...All these us spec luxury gadgets confuse me after awhile....:D

Tell me about it - I have no idea what the secret for that "starts in second" thing is.

I'm kind of hoping the Dr. can say!

Oh I know! I know there has been so many "debates" over it....over the years.....I know my personal haunted, one off 78 starts in 2nd unless I kick it down....but I've stopped trying to relay that :rolleyes:

Mine starts in whatever gear I want it to.

Yeah but only when your left foot is firmly down on the clutch pedal (or you happen to be flying down a steep hill at speed)!