downshift auto trans question
 

:) Hello, when going around 30mph and I let go of the accelarator, the car "downshifts" but with certain "bumping-shaking" coming from the transmission. It is an intermittent problem but has gotten worse today. I am thinking it could be the solenoid kickdown system. I took a picture of the pedal trying to find the "kickdown switch". Could this be the problem? Is that plastic round piece in back of the pedal the kickdown switch?

Thanks,
Adiel

heres the picture:

one more test I performed
 

Ok, I just got back from testing the car. This time I drove the car, the problem seems around 30-35mph when I let go of the pedal a bit. It tries to "downshift" but the car just really slows down...too much. The "bumping-shaking" does not happen every single time though. Next test I performed, I remove the connector in back of that little device I have on the picture above and now the problem happens every time I let go of the pedal when I am going around 30-30mph, it starts the "bumping-shaking" and the car really slows down. So it looks like the culprit is something in that system...anyone know exact which part would cause this problem?

Thanks,
Adiel

*bump*
 

:) Could the problem be that piece I am pointing to itself?

Thanks,
Adiel

:) Ok, so far I figured out that piece is the famous "kickdown switch", I pressed it and it does nothing, it does not go in or out. Is that working as designed?

Thanks,
Adiel

Kickdown switch should work when your cruising under 75mph or so in 4th, floor it, and you get 3rd gear. There is also a cable that controls such things that goes to the tranny. Your downshifts sound like high vacuum at the modulator, does it upshift hard?

I noted the same on my 81. Turns out the bowden cable was adjusted too much. I backed it off and the car quit trying to downshift so quickly.

Ok, I adjusted the bowden cable to be exact on idle. It was a little "loose". Now it still tries to downshift sometimes but at a higher speed. (again I have to let go of the accelarator just a tad bit and then it attempts the "downshift" which SLOWS the car down way too much)


Yes, it does upshift hard. I guess my next step is to take out the mighty vac and check to make sure its at 15 idle/0 full throttle?

Thanks,
Adiel

If you think it is possible the electric downshift is causing the problem, then to check that you should unplug it. There should be a single wire plugged into the tailshaft, above the driveline on the very rear of you transmission. Just unplug that and check the shifting pattern again.

:) Thanks, is this the cable you are referring to:

I think you are pointing at the speedometer cable!

:) It looked like the speedometer cable. Then where would the "electric downshift" cable be at?

Thanks,
Adiel

1983 300D

*bump*

:) Anyone know where the "electric downshift" cable is located?

Thanks,
Adiel

The kickdown solenoid is just out of view in the tranny picture. It is located at the right rear of the tranny, has a single pin connector and should accept a 19mm wrench if memory serves me correct.

:) Thanks Mike, I did not realize that the "electric downshift" cable and the "kickdown solenoid" cable was actually the same thing. I will be disconnecting the cable and see if the incorrect "downshifts" go away. My next question is, lets say the incorrect downshifts do go away when I disconnect the cable, would my next step be replacing the kickdown solenoid, the kickdown solenoid cable or the kickdown switch under the accel pedal?

Thanks Again,
Adiel