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#1
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87 TD shifting issue - advice needed
I now have an 87 300TD with about 8K on a rebuilt transmission, 265K on the car. Car has run quit well and shifted very well after replacing the sub-frame mounts. On a trip north after about 150 miles stopped at a rest stop. Started out of area and with significant traffic had to hit the accelerator to merge back in. The trans would not readily shift to 3rd without taking my foot off the accelerator and letting it slow quite a bit. Getting into 4th was just as troublesome. Made it to my destination....another 50 miles on two lane roads and just shut it off for the night.
Next day, the shifting from 1st to 2nd became an issue and it seemed to refuse to go to third. Under the hood the vacuum line from the intake manifold to the switch over valve was off....probably I thought because it was tight and the engine torque had just pulled it off. Put in new and longer hose but that made no difference whatsoever. So, I am not sure if the issue is the kick-down switch which can make such issues and is probably original OR if there is some new vacuum issue. The vacuum pump just up and failing does not make much sense. Any thoughts or suggestions will be greatly appreciated!! Frank
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old goat 86 300SDL - 207K 84 300DT - 298K - sold 78 450SL - 97K 61 Porsche - rare T-5 Karmann Hardtop - NO, NOT a Karmann Ghia 99 Suburban 4x4 - 247K all original, the family donkey |
#2
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You should be able to unplug the kickdown switch (underneath the accelerator pedal), to allow you to test drive without it. It sounds like yours is stuck.
Here's what you're looking for: Kickdown Switch (pictures)
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1982 240D, sold 9/17/2008 1987 300D TurboW124.133 - 603.960, 722.317 - Smoke Silver Metallic / Medium Red (702/177), acquired 8/15/2009 262,715 and counting |
#3
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Could also be a sticky bowden cable.
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1977 300d 70k--sold 08 1985 300TD 185k+ 1984 307d 126k--sold 8/03 1985 409d 65k--sold 06 1984 300SD 315k--daughter's car 1979 300SD 122k--sold 2/11 1999 Fuso FG Expedition Camper 1993 GMC Sierra 6.5 TD 4x4 1982 Bluebird Wanderlodge CAT 3208--Sold 2/13 |
#4
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I've had this same problem a few times with the same car.
The first was a loss of vacuum integrity, the second was corrected by adjusting the positioning cable that runs from the accelerator linkage to the xmission. The vacuum issue was a bit tricky to sort, but one of the modulators behind the right headlight was leaking internally, enough so it messed up the vacuum module controller on the side of the injection pump. The cable adjustment was an insidious decline, as opposed to what you're experiencing. The cable should be adjusted about 1-2MM short off the ball so when it's installed there is a slight tension.
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Mark ======== THE WHITE FLEET 2016 GLE300d 4-MATIC 38K BROWN! 2012 S350 Bluetec==94k WHITE 2007 ML320 CDI==166K WHITE (FOR SALE) Under new management: 2005 E320 CDI--140K--WHITE 1995 E300-Diesel-133.5K--THE CAR IS BLUE 1986 300SL--97.5K (European) AND WHITE. Back in Europe! 1991 190E 2.3-73K California Perfect.--WHITE 1995 E320-Wagon-159K--WHITE (recently scrapped) 1987 300D Turbo-213K--WHITE 1987 190D 2.5 Turbo-288K--WHITE |
#5
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Thanks for all the feedback so far. I do intend to unplug the kick-down switch....just as soon as I get back up there. I left the car there and got a ride home. I want to have everything I might need when I go back. The car is at a friends house so safe and sound.
I did check the cable best I could and appeared free and functional. As for the vacuum problem being the cause, I can check but could the leak be so bad the trans does not shift at all?? I did not look at the area behind the right headlight to check vacuum....lines or parts....but obviously will have to do that as well. Frank
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old goat 86 300SDL - 207K 84 300DT - 298K - sold 78 450SL - 97K 61 Porsche - rare T-5 Karmann Hardtop - NO, NOT a Karmann Ghia 99 Suburban 4x4 - 247K all original, the family donkey |
#6
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While it's good the cable is free, it must have the slight "preload" to ensure proper shift points.
But given your vacuum line or lines are off, all bets are off, the vacuum system has to be closed and functional, or all sorts of crap goes wrong, including no turbo and the climate control goes to defrost and sometimes the car won't turn off depending on where the breech is located. |
#7
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While it is true the one vacuum line was off, reconnecting it did nothing. So even as I know I have to check for a vacuum issue, the "all of a sudden" shifting problems does seem to point toward the kick-down switch potentially sticking during that hard acceleration.
I will just have to go back with hoses and vacuum gauge to find out what is happening.....plus plenty of tools and patience. If I can get it home then I have a warm garage to work on it. Thanks to all, especially Mark, for the comments and suggestions. Any other thoughts are most welcome. Frank
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old goat 86 300SDL - 207K 84 300DT - 298K - sold 78 450SL - 97K 61 Porsche - rare T-5 Karmann Hardtop - NO, NOT a Karmann Ghia 99 Suburban 4x4 - 247K all original, the family donkey |
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