w123 auto box adjustment

[stuarth]

I have a 240td with autobox (1981). It has only 80k miles from new. WHen the car changes gear from say, 2nd to 3rd, it overrevs a bit before the next gear is selected. I am told there are two adjustments - one determines WHEN the gears cganfe and the other determines HOW quickly or smoothly it changes. I beleive the latter is an actuator screwed into the side of the gearbox but this is all I currently know.
Can anyone enlighten me on how this works and how to adjust things assuming my diagnosis is right?
thanks

 

[stuarth]

I may have found the solution on Youtube here
Mercedes Diesel Transmission Adjustment - YouTube

Perhaps you can look at this and tell me if it is the same for my car? Seems pretty simple if it is right

 

[jaymanek]

Very similar but the adjustments are very hit and miss... I once wasted a complete saturday adjusting, test driving, adjusting and on and on..

 

[stuarth]

Anyone have any ideas about how to make it non-hit and miss? There must be some sequence in which this has to be done and presumably the video has this right but also some adjustments? I would be tempted to take out the gearbox actuator first to see if it works.

 

[krimat2005]

check this out
http://avtopedia.ru/akpp/722-3 722-4.pdf

 

[stuarth]

If I change the vacuum control unit on the gearbox, does it have to be the same colour coding as the one I remove? The only one I seem to be able to get in France is the GREEN coded one.

 

[krimat2005]

yes it has to be the same colour, and after that you have to check/adjust working presure. all in the link i posted couple days ago.