FMX and C6 flexplates

Discussion in 'General Automotive Questions' started by handy_andy_cv64, May 16, 2019.

  1. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    '76 LTD, 400/FMX, it's on wobbly legs right now, it's abused, doesn't shift right, yadda yadda. The question is, if the trans gets replaced by a C6, is the flexplate the same? A yes answer would make things easier, but not impossible.
     
  2. aquartlow

    aquartlow In Maximum Overdrive

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    IIRC, they will not interchange. If I was removing a transmission from a 40+ year old vehicle I would replace the flexplate anyhow due to years of use and the occasional starter grind that could have happened during it's lifespan. For usually less than $40, purchasing and installing a new/correct flexplate is just cheap insurance against doing it again, just saying.
     
    andrewok1 and pmrphil like this.
  3. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    Good reasoning, even if they were interchangeable. Thank you.
     
  4. colnago

    colnago In Overdrive

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    I agree. Had the flexplate crack on my '67. Took it to a shop (they had the tools; I didn't), and it cost $300.

    Joseph
     
  5. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    Hey, bringing up this thread, since I was the OP, but I'm working on my friend's FMX for shifting problems, and one of the overlooked things, generally, is the governor. I've removed the gov assembly from his, and it is craptastically clogged with gunk. I'll also pull the modulator, just to check it, and then road test it tomorrow.
     
  6. Jeff B

    Jeff B In Maximum Overdrive BRONZE MEMBER

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    If you change your flex plate, does that affect the harmonic balancer or the balance it balances? (That is a technical question)
     
  7. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    The flexplate is more or less matched to the crankshaft and damper. My original question was if a C6 replaced an FMX, would the flexplate need to be changed to accommodate the trans. That means the new flexplate is still usable on the engine.
     
  8. Doc76251

    Doc76251 In Fourth Gear

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    The flex plate is the big gear that makes the little gear on the starter roll the engine over. That said there are balanced cranks and unbalanced cranks that can use the fly wheel as a location for balance weights / holes. Replace what you took off with the same thing. The harmonic balancer in the front of the motor dampens the vibrations associated with the timing chain gears, belts and such. HB's are REALLY important to your "V"/ serpentine belts as my son found out on his Subaru when the freshly installed motor stared eating accessory belts. The HB had come "unglued" and the outer ring was walking it's back towards the engine block eating it's way into the serpentine housing.

    Cheers,

    Doc
     
  9. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    Ouch. I had given my niece a '93 Taurus that ran great for me, but needed a bunch of repair work. I did all the work, she took it to college...and then the idiotic s#!t started happening. Dying when hot, and developing a wicked vibration like it was on four cylinders out of six, I had to go down to try to figure out what was wrong. I finally figured out a wire in the ignition was broken and would open once hot, and the damper ring slipped. I had to go from Salem up to Portland for a used damper because the three yards in Salem didn't have any 3.8L engines.
     

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