240D 1983 Transmission problems...

[kabtv]

hi everybody, i got a beautiful 240d 1983 and after reading almost every post on this forum about the strange relation between owner and his transmission, a lot of questions were answered but one... Where is the Bowden Cable on my car ???
I looked everywhere and found nothing...And if there is no Bowden Cable, what is replacing is function on my model. I thing that my trans. model number is 722.118.
I'm not a mechanic, even after what i read here in the last two days(i thing than i know much more then my mechanic )
But now it's begin to be a nightmare...i went to my mechanic last week with two transmission problems:
First: no kickdown,
Second: shifting at very hight rpm between 2-3 and 3-4
From there, i was(after reading some posts here) sure it was nothing(almost, we never know...)
But my mechanic return my car with three problems:
First: Still no kickdown,
Second: lost of power(even with the pedal to the ground),
Third: slipping shifting between 2-3 and 3-4 but only if i put the pedal to the ground and like i got no HorsePower...
and an invoice of +300$.
Any Clues...

p.s.: i checked for my kickdown buttom and i realized then the pedal rod cannot touch it !!!???!!!
p.s.2.:I'm looking for a good mechanic who can fix that, in the Montreal, Quebec area.

[mbdoc]

Vacuum controls ALL of the shifting aspects on THAT transmission.

Too much vacuum & the trans shifts too early & soft.

Not enough vacuum & the trans shifts late & hard.

Vacuum controls are left to the expert....

[kabtv]

thanks for your reply but my problems are still there. i try to collect infos to give to my mechanic(that's ironic, i know... ) i found very interesseting links and infos but they all talked about the bowden cable as an important part in the process of the fine tunning but i don't have it on my car . Apache told me that The modulator determines shift timing and the vacuum input to the modulator controls the firmness of the shift and about an electric kickdown button below the accelerator but that's about it. he didn't tell me how to adjust it...??? or how to fix it ???
Why my pedal didn't touch the kickdown switch ???
(It's not because of the carpet...)

[nhdoc]

Originally Posted by kabtv

thanks for your reply but my problems are still there. i try to collect infos to give to my mechanic(that's ironic, i know... ) i found very interesseting links and infos but they all talked about the bowden cable as an important part in the process of the fine tunning but i don't have it on my car . Apache told me that The modulator determines shift timing and the vacuum input to the modulator controls the firmness of the shift and about an electric kickdown button below the accelerator but that's about it. he didn't tell me how to adjust it...??? or how to fix it ???
Why my pedal didn't touch the kickdown switch ???
(It's not because of the carpet...)

If your pedal won't reach the kickdown then the linkage which is under the hood between the pedal and the injector pump is out of adjustment. There are several adjustable links and a procedure to make sure that you get full engagement of the injector pump control at wide open throttle (WOT). These links also effect the shift controller, so this could all be related.

As for the transmission problems the vacuum switch mounted on the top of the valve cover is what tells the transmission modulator how far open the throttle is. You may have a problem with the vacuum switch or it may be related to the linkage being so far out of adjustment. Often times those vacuum valves leak and cause late/harsh shifts. They are inexpensive parts to replace ($30 or so) and only one is for the transmission, the other one is for the EGR valve. When it is right you will know it, the transmission will shift smoothly and just at the right time, every time. YOU DO NOT HAVE A BOWDEN CABLE ON THIS CAR - FORGET ABOUT THAT!

My advice is to either learn what you need to in order to fix this yourself or find a tech with experience on these older MBs (try finding an older person...preferably a tech who doesn't have all of his own teeth). It's not rocket science, but the first time you tackle it can be time consuming. For someone with experience it would take him under an hour to get you straightened out...that should be about $100 plus the $30 vacuum switch part, more or less.

[kabtv]

thanks Marty...
your answer give me courage and hope...

i found an interesting article by Dan Penoff name ``Adjusting the transmission on your 123 or 126 Diesel`` and i'm going to bring it to my mechanic if i don't find an another one before.

i thing than i'm going to change the modulator on the transmission ....and change the transmission oil in the same time. i read in an another post than the major upgrade in the vacuum system was the modulated vacuum(VA) for the amplifier(A big blue vacuum).
Do you thing i can upgrade my system with this...is this reliable ???
KarL
p.s.: do you know what is the utility of the two switchover valves on the top of the valve cover ???

p.s.2.:last minute update, i just found this post by ``240 ed`` in dec 2001:
``Quick fix idea!! On the trans modulator, (mine is red plastic with a white cap for the vaccuum line). Pop off the white cap! Carefully pry it off with a screwdriver or whatever. On the red modulator, you will see an O-ring. Pop it off, and go to the parts store and get a new one!
I bet that will bring your shifting into line. As far as I can tell, this is the only wear item in these modulators, so i wouldn't spend the money for a new one, until you replace this O-ring.``
What do you think about it ??

p.s.3.: speaking of leaking, i got water going in my trunk(right side only), visibly by the rear seal window(it' kind of dry and the trunk seal is like new) but with my last mercedes(240D 1980 4speeds manual so no transmission problems) i had the same thing and changed the seal but with no resolve...water was still leaking in the trunk...so before before my mechanic ask me to much money for this, any advice ???

[kabtv]

You know, ajusting a Mercedes Tranny is fleerting with desesperation.
Everything in the vacuum system is o.k., pressure o.k., switch o.k., there is no leak with the modulator but I tried to ajuste it and nothing happen!!! I turned it three full turn clockwise and the transmission is still shifting too soon and too smooth...and slipping between 2-3. i was thinking about the k1 upgrade kit and i was wondering if there is a kit like that for a 240D 1983? if yes, may i ask you the part number ? Or perhaps it's something else...!!!
I need you help here guys!!!
Thanks.

[kabtv]

hi thanks for taking time to help me to resolve this nightmare...
i tried disconnect the vacuum line going down to the modulator, and went to a road test to see what change it makes.. nothing, nada, rien du tout...
you know, i don't have a space to do mechanic on my car so i go to a mechanic. in this case two, i went to two different mechanics to fix the transmission. More than 500$ later nothing is fix. it shifted too soon and it slippind between 2-3 and 3-4.
So i decided this afternoon to do the job by myself, i bought a Mytivac, park the car on the street in full sun(It's still cold here in Montreal) and did the pressure test and here are the numbers:
1-Vacuum from the pump : 25
2-Vacuum before the green Surge damper : 17.5
3-Vacuum after the green Surge damper : 17
4-Vacuum at the exit of the vacuum control valve(idle) : 0
yes... 0
Now my question is: do i take the vacuum correctly ?
if i well understand, there is a line(with the green Surge damper) bringing vacuum at the top of the vacuum control switch then going out by the side of the valve(near the adjustment bolt) going to the switchover valve then to the transmission. I did plug the mityvac near the adjustment bolt
Am i right ?
i just talked with one of the mechanics and he tolds me than he never, in his career, he changes a vacuum control valve....so can i fix the valve ??? Or should i change it ? If i try to adjust it(with the bolt) what are the effect i mean if i turn clockwise?
thanks again...
KarL