'67 Barracuda Fastback S 383 4 speed rear end issue?

Manual Transmission & Clutch Discussions

  1. Dennis Jackson

    Dennis Jackson Active Member

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    New owner here, and my questions are piling up. My noob status is quickly becoming apparent, so sorry for that. I think I may have an intermittent problem with the 3.23 sure grip rear end, but I'm not sure, so...

    According to the previous owner, the car has a new McLeod diaphragm style clutch & throw-out bearing, flywheel was resurfaced, clutch linkage was rebuilt, and shifter was upgraded to a Hurst Competition plus conversion from the original inland shifter mechanism, so I'm assuming it is not a clutch issue. I am not aware of any work done to the rear end, so I'm assuming that is original and 53 years old. Here is the symptom as best I can describe it...

    It happened a couple of times on the test drive, and I assumed it was just my inexperience with driving it, but now I am questioning that. When starting from a dead stop in first gear, I get what I can only describe as a severe shuddering of the rear end. It feels like the tires are wanting to spin, but they won't let go and the whole car shakes until i disengage the clutch, give it more throttle, and slowly re-engage the clutch (sometimes a few times) until I get it going smoothly.

    After buying the car and getting a better feel for driving it (I have had it a week), I went a while without a problem, but now it seems to be happening again intermittently. I swear the clutch action feels different when it happens, and I don't think it's me. The clutch action feels 'normal' most of the time and I don't have issues up shifting or down shifting gears 2, 3, or 4. Does this sound like a problem with the drive train or the driver? I have as of yet not intentionally tried to do a burn out. I have been in 'baby it' mode for the most part up to this point. Any sage advice to an admitted greenhorn would be most appreciated. Thanks
     
  2. Oldmanmopar

    Oldmanmopar Going left turning right FABO Gold Member

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    Does this happen when pulling out around a turn or going straight? Around a turn it could be the clutches in the sure grip which is normal. Just let the clutch fly and drift the turn you won't hear any noises.

    You mentioned it has a diaphragm clutch. Is the large overcenter spring still on the peddle assembly under the dash? It shouldn't be. A diaphragm plate does not need a over center spring. It will be noticable on the engagement on a RPM shift or pulling out .
     
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    • A56

      A56 MoParAffliction FABO Gold Member

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      Sounds to me as if the clutch is giving you the problem. You could elevate the rear of the car and do some basic investigation.
       
      Last edited: Jun 29, 2020
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      • Dennis Jackson

        Dennis Jackson Active Member

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        Now that you mention it, it may be happening more on turns, but I would swear it has also happened on a straight away. I will pay more attention going forward and try what you suggested. I looked at the clutch pedal and could not see anything that looks like a spring on the mechanism.
         
      • A56

        A56 MoParAffliction FABO Gold Member

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        Well, I would definitely crawl under there sooner than later or have the previous owner informed of your concerns before some nightmare ruins the car and your day. That can only get worse.
         
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        • ZMan67S

          ZMan67S FABO Gold Member FABO Gold Member

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          Here is a picture showing its location. Its a good size spring. You have to get under the column and look up for it.

          upload_2020-3-23_11-32-53-png.png
           
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          • kursplat

            kursplat FABO Gold Member FABO Gold Member

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            it can blend in pretty well, here's a pic of a B body setup for reference
            IMG_4194.jpg
             
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            • A56

              A56 MoParAffliction FABO Gold Member

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              There's a thread on here somewhere about clutch adjustment that you may want to visit. Type in "clutch adjustment question" in the search box
               
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              • Dennis Jackson

                Dennis Jackson Active Member

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                Thanks to you both for the visuals. It definitely does not have the spring installed. I can see the attachment point where the spring would go. I did note however that the spring attachment point is making contact (rubbing against) it's neighbor to the left, the parking brake bracket. It doesn't look like the interaction would ever be enough to block movement of the clutch pedal, but there are definitely metal filings on the outer surface of the clutch spring attachment point.
                 
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                • teringer

                  teringer ase master hall of fame FABO Gold Member

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                  you might be getting oil on the clutch and not slipping when hot just grabbing
                   
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                  • my68barracuda

                    my68barracuda Well-Known Member

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                    Verify that the motor mount bolts, motor to bell housing to transmission bolts transmission mount bolts are all preset and tight.
                     
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                    • RedFish

                      RedFish Well-Known Member

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                      Something very simple to try... get a bottle of Fords friction modifier and pour it in the differential. If they've never changed the formula of this stuff, don't spill a drop! Its smell registers right there with a dead skunk. Vapors from the empty bottle would clear the break room.
                       
                      Last edited: Jun 30, 2020
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                      • Dennis Jackson

                        Dennis Jackson Active Member

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                        :rofl:
                         
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