Car does not have to be running. You may have to elevate it to see the transmission connection or not. I guess it depends. What you want to establish is that as the linkage to the injection pump is advanced. That there is a corresponding movement on the bowden cables transmission end and that it is moving the activation device on the transmission. My guess is that if there is good movement under there that the control the cable is changing is not working inside the transmission.

Even if this becomes the case it should not require removal of the transmission. That control rod probably controls something in the valve body. I am not a transmission type though remember.

The turbo has basically no effect unless the engine can rev up beyond 2000 rpms has to be kept in mind. Early shifts up do not allow this. On slow acceleration such a situation is okay. Still when you want power the engine revs before the shift points must be well over 2000. The bowden cable enables much later shifting up under demand from the linkage to the injection pump. For example if the accelerator pedal is 3/4 down the shifts may be delayed until 3500 rpm is reached by the engine.

If you have driven other cars with automatic transmissions you probably have noticed that the more fuel given the later the transmission shifts will be. This is by design even with non turbo cars but especially required on turbo engines to get the benifit of the turbo.

Thanks Barry for your advice. I will take heed and I will follow-up.

It is just where I would look for the problem first. The linkage at the transmission the bowden cable controls may be suspect. The control rod usually has to be hooked up to the valve body when the transmission is put back together. Maybe not on this brand.. Still this may just have been missed is still a possibility.

My own particular issue was when I purchased an old 114 gas mercedes for the transmission. It too held the shifting up too early points on accelleration.

Like yours they remained the same no matter how much or little I gave the pedal. One of the controlling rods ball joints had rusted apart. The rod served the same purpose as your bowden cable does.

It is all starting to come back to me... On the SDL there is an electronic kick down switch under the accelerator. Check to see if the carpet or floor mat is interfering with it. It runs off the same circuit as the mono valve for the heat, so if you have heat all the time, the fuse could be blown. I found this out after the insulation wore out on the kick down in my SDL and the cabin heated up!

If you are running and you floor it, does the transmission drop into a lower gear?

I think the Bowden cable was probably left disconnected by the transmission shop...

Did you check out the remainder of the linkage other than the bowden cable?

If the linkages that control the IP/etc are out of adjustment or something, they can easily cause problems.

Just for the record here in this thread. I had the transmission removed from my 87 SDL to replace seals, gaskets and pump. When I got it back the shift points were all at higher RPM and it was due to lack of power because the turbo was not working properly because the vacuum line to the ALDA was left un-connected. Once I discovered this it was like getting a new car back. Much more power and shift points were back to normal. It was a simple fix to clean out the vacuum line and hook it up where it belonged.

Great that it was fairly simple and did not involve The internal trasnsmission parts in the end.

Plus thanks for mentioning on site what you found.

A question on the 87 300sdl ,does it have the linkage joint at the firewall from the accelerator pedal like the 77-85 300d ? If it has anything similiar to this plastic ball assembly I would check this for failure .Lube up all your throttle links from the accelerator pedal to the throttle rack with lithium grease ,then I would find any possible points of failure for the throttle .This could easily be a bent linkage rod also for one important fact and that is to remove this transmission a gorilla wearing overalls with a pry bar in hand was inside that motor area freeing up the old trannie off the motor.

1987 mercedes-benz 300d transmission problem
 

Hi everyone, my 1987 300D doesn't shifts to 4th gear. Before didn't shift to 1st and I have replaced Brake Band B1 and got it to work. Now 4th gear is not working, could that be Brake Band B2? Checked all clutches they look fine, thank you for any help

The most common reason for this is that the kickdown switch is shorted. Unplug the kickdown solenoid and see if the problem goes away. If it does, replace the switch.