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88 Cherokee Piston Slap? Nope, Cracked Flexplate

Discussion in 'Quitters' Club' started by Focker, May 30, 2017.

  1. Jun 2, 2017
    Glenn

    Glenn Kinda grumpy old man Staff Member Sponsor

    Apopka, Fl
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    Your first video of the timing chain sounds like the original slap you were hearing. Doesn't it actually run good?
     
  2. Jun 2, 2017
    PeteL

    PeteL Member Sponsor 2019 Sponsor

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    Well. That certainly could make a slapping-like noise.
     
  3. Jun 2, 2017
    Daryl

    Daryl Sponsor Sponsor

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  4. Jun 2, 2017
    Focker

    Focker That's what I do, I know things and I fix stuff. Staff Member Sponsor 2019 Sponsor

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    It wasn't bad while driving it home.
     
  5. Jun 2, 2017
    Focker

    Focker That's what I do, I know things and I fix stuff. Staff Member Sponsor 2019 Sponsor

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    Tempting, but not yet.

    THANKS... I appreciate it because I know you would do it for me!
     
    Daryl likes this.
  6. Jun 2, 2017
    Focker

    Focker That's what I do, I know things and I fix stuff. Staff Member Sponsor 2019 Sponsor

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    I found numerous videos last night backing this up. This is today's task.
     
  7. Jun 2, 2017
    Focker

    Focker That's what I do, I know things and I fix stuff. Staff Member Sponsor 2019 Sponsor

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    Pulled the plugs and turned the crank and I have to pull quick to make it knock. If I just turn, nothing. I get the knock around piston 5 or 6...Then I keep being drawn toward the transmission. If I put my hand on the bell housing I don't feel the knock as much as I do when I let my fingers drag on the flexplate.

    My neighbor came over and rocked the crank back and forth. You can hear it resonate down the crank, but I had my hand on the flexplate and there feels like a 1/4" to 1/2" of slack back and forth before the knock.
     
  8. Jun 2, 2017
    ITLKSEZ

    ITLKSEZ Volvophilic

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    Interesting.
    I'm so intrigued by this, I wish I had time to run down there and check it out with you.

    I went back and listened to the first video again. It really does sound like an external vibration. Like an issue with the torque converter. It just runs too quietly and smoothly in between knocks to point towards a rod or cam issue, IMO.
     
  9. Jun 2, 2017
    ITLKSEZ

    ITLKSEZ Volvophilic

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    I just texted a buddy of mine who knows those engines a link to that video. His immidate response was "The starter is loose and knocking on the block."

    Any chance you checked that?
     
  10. Jun 2, 2017
    Focker

    Focker That's what I do, I know things and I fix stuff. Staff Member Sponsor 2019 Sponsor

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    Me too.
    I totally agree.
    I did...Not the starter. I thought that maybe there was some starter gear chatter also, but I could pull the starter out of the way and rock it some more?
     
  11. Jun 2, 2017
    Focker

    Focker That's what I do, I know things and I fix stuff. Staff Member Sponsor 2019 Sponsor

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    Not sure what that means, but now I used it in the next video. :rolleyes:
     
  12. Jun 2, 2017
    Focker

    Focker That's what I do, I know things and I fix stuff. Staff Member Sponsor 2019 Sponsor

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    Here is a video of the rocking back and forth. I'm afraid now that it might be a main bearing? :worry: :mad:

     
  13. Jun 2, 2017
    ITLKSEZ

    ITLKSEZ Volvophilic

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    Is there any discrepancy between the movement of the crank and the flex plate? If the crank-to-flex plate bolts were loose (or the flex plate-to-torque converter bolts) you'd get a knock like that, plus a resonating knock while running, like you have. Squeeze a wrench up in behind the flex plate to make sure the bolts are tight. They can back out if threadlocker isn't used.

    I guess it could be a bad or non-existent rod bearing, but it doesn't make sense why you wouldn't hear it constantly.

    Scotty, beam me down to Focker's coordinates.
     
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  14. Jun 2, 2017
    Focker

    Focker That's what I do, I know things and I fix stuff. Staff Member Sponsor 2019 Sponsor

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    I removed the starter just to eliminate another possibility...It's not the issue.
    I'll look into this...Not sure how? All I see is the flexplate.
     
  15. Jun 2, 2017
    Focker

    Focker That's what I do, I know things and I fix stuff. Staff Member Sponsor 2019 Sponsor

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    This is very close to what I think mine sounds like.
     
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  16. Jun 2, 2017
    ITLKSEZ

    ITLKSEZ Volvophilic

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    Did you read the comments? His issue was bolts missing/loose from crank pulley. But he also replaced the flex plate, soooo... who knows.

    BTW, don't run your engine like that, with the TC unbolted. It will make a mess of the crank.

    There are three bolts that hold the TC to the flex plate. They go into the TC through the flex plate from the engine side. You have to spin the assembly to get to them one at a time. Usually you can only get to them with an open-ended wrench, which is why they can come loose. They are hard to get tight enough.
     
  17. Jun 2, 2017
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member Sponsor

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    I'd think that the torque converter not spinning would be a good clue...
     
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  18. Jun 2, 2017
    Glenn

    Glenn Kinda grumpy old man Staff Member Sponsor

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    Yours does sound a lot like that, although it's less consistent.
     
  19. Jun 2, 2017
    Glenn

    Glenn Kinda grumpy old man Staff Member Sponsor

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    I was kinda wondering about that Howard, but it drives? Was driven to his home.
     
  20. Jun 2, 2017
    ITLKSEZ

    ITLKSEZ Volvophilic

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    I think the TC in that last video was seperated to try to diagnose a problem. Find out if it was engine or transmission. Without the trans spinning, it must be on the engine side.
     

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