Ok this is new for me. Can you give me any tips on adjusting it? Is it done at the carb or trans end?
Dan, you are truly a font of knowledge.
I am pretty sure your brain just crowded out your hair!
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| Car shaking on acceleration https://slantsix.org/forum/viewtopic.php?t=49012 |
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| Author: | Shrug64 [ Fri Jun 08, 2012 2:16 pm ] |
| Post subject: | Car shaking on acceleration |
OK, when I accelerate from a stop, my car first, shifts in to drive almost immediately. Then if I accelerate too hard the car shakes a lot. If I back off just a little it smooths out. I have to accelerate slowly. Same if I try to hit it while moving. I have to downshift to second and slowly give it gas or it will shake. Any ideas? Motor, carb, tranny? When the engine is idling, it sounds fine, smooth. When I get up to speed, city or highway, it is smooth. I got on the freeway the other day and it took a while to smoothly accelerate to 65 and then it was fine. When I try to give it too much gas to pass somebody, same thing, some shaking. I have to have just the right combo of shifting and accelerating to keep it smooth. I really need to know what to fix! Thanks! |
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| Author: | Doc [ Fri Jun 08, 2012 2:22 pm ] |
| Post subject: | |
Sound like a worn-out front Ball & Trunion u-joint. (driveshaft shake) DD Edit: Not a B&T u-joint in this case, I based my "guess" off the 64 1/2 B-cuda in the poster's signature... sorry. |
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| Author: | Mroldfart2u [ Fri Jun 08, 2012 3:14 pm ] |
| Post subject: | Re: Car shaking on acceleration |
Quote: OK, when I accelerate from a stop, my car first, shifts in to drive almost immediately.
I would say check all band and clutch adjustments in the trans... If it is shifting to 'drive' (3rd) that quickly, then its a trans related problem. IE: kickdown linkage adjustment and or bands clutches adj... Not to disagree with Doc, as i have never dealt with the ball and trunnion style driveline..... M2C
Thanks! |
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| Author: | 87D100 [ Fri Jun 08, 2012 4:01 pm ] |
| Post subject: | |
could also be a secondary ignition misfire.... e.g. plugs, wires, cap, rotor, etc. Tune up parts will started acting up under heavy load before they cause problems at idle/cruise low load situations Kevin |
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| Author: | Shrug64 [ Fri Jun 08, 2012 5:03 pm ] |
| Post subject: | |
I thought it might be a trans problem. I do not know what a ball and trunion is. The car I am talking about is a 1952 Chrysler Windsor with a 318 and torqueflite tranny out of a 1989 Diplomat. What is the latest model tranny I can pick up from the junkyard? If the tranny repair is too costly that is. 30+ years working on cars and I have never mastered trannys or suspension. |
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| Author: | Fopar [ Fri Jun 08, 2012 5:28 pm ] |
| Post subject: | |
The 89 trans should not have ball & trunion should be a "u-joint". Richard |
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| Author: | sandy in BC [ Fri Jun 08, 2012 5:31 pm ] |
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Does the starter not hit the steering box on this car? ....sounds like a torque convertor problem. |
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| Author: | Shrug64 [ Fri Jun 08, 2012 5:34 pm ] |
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I will have to crawl under the car and have a look around. |
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| Author: | Shrug64 [ Fri Jun 08, 2012 6:14 pm ] |
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Oh also I was told it was a torqueflite, how do I tell if it is a 727 or 904? |
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| Author: | Shrug64 [ Fri Jun 08, 2012 6:31 pm ] |
| Post subject: | |
OK, I got under the car and it looks like I have a 904 trans. If it makes a difference. |
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| Author: | SlantSixDan [ Fri Jun 08, 2012 6:40 pm ] |
| Post subject: | |
Ball-and-trunnion: Not applicable; not used in the powertrain you pulled out of the '89 car (last year for B&T type front universal joint was 1965). Sounds like probably a less-than-complete installation/adaptation of the later-model powertrain into the early car. Immediate shift out of first and second into third: "kickdown" (throttle pressure) linkage that tells the transmission how far open the throttle is, is missing or broken or not adjusted correctly. Setup from the '89 car would very likely not have fit your hot rod, so might have been left off altogether. See this thread for kickdown options. Running trans without kickdown will cook it in short order; in the meantime yes, it will judder when you apply gas because you are lugging it in top gear when it still needs to be in 1st or 2nd to get that heavy car up to speed. Meanwhile, the lockup torque converter doesn't know what it's supposed to do because of no kickdown linkage and/or no electric hookup, depending on which style of lockup torque converter you have. Probably electric in '89. Look at the driver's side of the transmission, near the rear corner of the transmission pan, and see if you see a one- or two-wire socket pushed onto a connector protruding from the transmission (or if no wire/socket, look for just the connector). Install and/or adjust kickdown correctly, if you have electric torque converter then hook that up correctly (ask on here), change the transmission fluid and filter, and then if symptoms persist ask more questions. |
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| Author: | Shrug64 [ Fri Jun 08, 2012 7:19 pm ] |
| Post subject: | |
I do have a kickdown cable. That sounds like a likely problem. I guess I can fiddle with the adjustment and see what happens. I had noticed that the car never downshift even when I stomp on it. Do you think I should replace the modulator too? Does the 904 even have a modulator? Transmissions make me cringe! |
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| Author: | SlantSixDan [ Fri Jun 08, 2012 8:40 pm ] |
| Post subject: | |
There's no modulator; that was GM's method. The throttle pressure linkage (cable in your case) does the job. Sounds like yours is way too slack. |
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| Author: | Shrug64 [ Fri Jun 08, 2012 9:14 pm ] |
| Post subject: | |
Ok this is new for me. Can you give me any tips on adjusting it? Is it done at the carb or trans end? Dan, you are truly a font of knowledge. I am pretty sure your brain just crowded out your hair!
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| Author: | SlantSixDan [ Fri Jun 08, 2012 9:55 pm ] |
| Post subject: | |
Glad to help when I can, but I can't comment on adjustment since a cable isn't a factory setup. Don't know whose cable and how it's configured. Could have adjustment provisions at the top, at the bottom, or at neither. Also, geometry matters -- there are many different kickdown levers (the lever on the trans which the cable pulls or pushes) with different lengths and indexing. This is going to take some doing! To try getting you pointed in the right direction: the kickdown lever should be all the way at its forward stop with the carburetor's throttle in the curb (hot, slow) idle position. The kickdown lever should begin to move at exactly the same instant as the throttle begins to move. The lever should be at its rearmost stop with the carburetor throttle wide open. If all three of those cannot be achieved at the same time, you'll have to find and fix the screwed-up geometry in the system. |
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