+- STD (https://www.superturbodiesel.com/std)
+-- Forum: Tuning (https://www.superturbodiesel.com/std/forumdisplay.php?fid=6)
+--- Forum: Drivetrain (https://www.superturbodiesel.com/std/forumdisplay.php?fid=9)
+--- Thread: What could be the cause for not downshifting? (/showthread.php?tid=3220)
What could be the cause for not downshifting? - fehron - 01-03-2012
I have a 82 240D automatic that has been sitting for a while. It starts and shifts all the way through the gears only with the pedal on the floor and once in top gear, it doesn't downshift. I have vacuum issues and have read that the vacuum effects shifting, but what I've read is that vacuum problems will just make it shift rough. Is that correct? What do you think my problem is?
RE: What could be the cause for not downshifting? - larsalan - 01-03-2012
Bowden cable is WAY too tight?
RE: What could be the cause for not downshifting? - aaa - 01-03-2012
Way too loose more like. Possibly not even connected.
RE: What could be the cause for not downshifting? - Hercules - 01-03-2012
Tight bowden cable,(late hard shift),possible no shift into first gear coming down.Very loose cable or off,(early light shift)no matter where pedal is at. No vac. to trans. modulator High hard shift,but will shift down after stopping,same with bad modulator. Sticking bowden cable (linkage arm) can cause varied problems. Combination of all is also possible. Good luck.
RE: What could be the cause for not downshifting? - fehron - 01-04-2012
I'm looking at my service manual and don't see a cable on the transmission. Are you referring to the pressure rod? I'll take a closer look at the car when the sun warms things up a bit.
RE: What could be the cause for not downshifting? - larsalan - 01-04-2012
Cable runs up the passenger side to the top of the valve cover. Connected to the throttle linkage. There is a plastic adjustment for it. Mine is broken. And the metal piece that it's all connected to can be bent back and forth too. Cable should have some tension on it. Not flopping all around but not tight like a piano wire either. I say about 1-2cm deflection, like one fingers worth or more.
RE: What could be the cause for not downshifting? - willbhere4u - 01-04-2012
Is there an electrical switch under your gas pedal? On my car it was broken and would not downshift to pass other cars
RE: What could be the cause for not downshifting? - aaa - 01-04-2012
The earlier models did have a rod instead of a cable. I didn't think 82 would be early enough though.
RE: What could be the cause for not downshifting? - fehron - 01-05-2012
(01-04-2012, 10:59 AM)willbhere4u Is there an electrical switch under your gas pedal? On my car it was broken and would not downshift to pass other cars
Yes, mine does have the switch under the pedal. It seems to be intact and clicks when I press on it. Is there a way to test it? dose this switch go to a fuse, and if so, which one? My fuse box is missing the diagram and I do have a fuse blown that I don't know what it goes to.
There's no cable connected to the linkage on top of the valve cover, just lots of linkage and vacuum lines. I don't see where one would be connected, but that doesn't mean I'm not missing something. None of that linkage appears to go back to the transmission. The vacuum/linkage is made up of a white cam that rotates actuating two white switches connected to the vacuum lines(if that helps).
Can someone post a picture of the cable in place. I googled it, but the images are hit or miss.
RE: What could be the cause for not downshifting? - larsalan - 01-05-2012
![[Image: 33525d1148789074-throttle-linkage-questi...n_idle.jpg]](http://www.peachparts.com/shopforum/attachments/diesel-discussion/33525d1148789074-throttle-linkage-question-300d-1985-california-300d_throttle_question_idle.jpg)
This is what I thought it should look like. I never heard anything about this rod setup ya'll are talking about.
See that part with the accordion style rubber thing on it.
that arrow is not mine just one that happens to be in the photo
RE: What could be the cause for not downshifting? - fehron - 01-11-2012
After more driving and testing, I need to re-explain my problem. I originally was dealing with multiple problems such as weird transmission shifting and WAY under powered on the highway. I was on the highway doing all I could to maintain 60mph and the car continued to slow down without downshifting from 4th to 3rd. I have at least improved the engine performance a little bit.
I can feel the button snapping under the pedal when mashed and I now know that it does downshift in the lower gears such as 3rd down to 2nd and it will eventually shift out of 4th, just at a very low speed.
I definitely have no cable and no push rod between the throttle and transmission.
Thanks for the info so far.
I started a new thread related directly to the vacuum situation if anyone can help out with that mess.