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Someone splain it to me

Discussion in '6.9L IH & 7.3L IDI Diesels' started by SkipBurney, Oct 24, 2020.

  1. SkipBurney

    SkipBurney Full Access Member

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    I keep hearing about dual mass flywheels but in all my life all I have ever seen on cars, trucks and tractors has been a flywheel, clutch disc, pressure plate and release bearing. What is a dual mass clutch setup.
     
  2. Clb

    Clb Another old truck Supporting Member

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    Look up class 8 tractors....60's pete, freight shakers, ext.
    Basics 2 friction plates and a sudo center flywheel.


    Think top fuel lockup without the techno stuff
     
  3. IDIBRONCO

    IDIBRONCO IDIBRONCO

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    I know what they are, but I can't really describe them.
     
  4. Clb

    Clb Another old truck Supporting Member

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  5. 79jasper

    79jasper Chickenhawk

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    Pretty simple to Google those.
    There's also dual disc clutches.
    Even many newer vehicles run a dual mass flywheel. (I'm about to really throw your head through the ringer) our 2010 vw jetta tdi had a dual mass flywheel on the dsg. (Auto trans) The dsg in itself is another humdinger. Lol

    Sent from my SM-N960U using Tapatalk
     
  6. Clb

    Clb Another old truck Supporting Member

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    ^^^ Hitler's Revenge!
     
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  7. u2slow

    u2slow bilge rat

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    In a nutshell, the flywheel is 2 slabs of metal instead of 1, with damper springs in between.

    The corresponding clutch disc typically lacks damper springs.
     
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  8. franklin2

    franklin2 Full Access Member

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    The diesel engine hits so hard when it fires, it shakes or "rattles" the drivetrain, especially the aluminum zf 5 speed. This makes a lot of noise.

    The dual mass flywheel helps stop this noise. Like others have said, it's a two piece flywheel, the large outside piece with the starter teeth on it, and it has a large pocket or inset in the middle where another flywheel resides and this is what the clutch is bolted to.

    Connecting the two flywheels together are lighter springs around the OD of the inset to help get rid of or dampen the noise, and there is a center clutch section with bevel washer springs which are there to protect the transmission from over torque. Yes hard to believe, but the factory thought the stock NA 7.3 needed a safety clutch in the flywheel to protect the trans. There is no solid connection from the engine to the trans. I believe I read that some guys that turn their trucks up with turbos on them have had this section of the DMF start slipping on them.
     
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  9. SkipBurney

    SkipBurney Full Access Member

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    Ok now I have got it one of my Massey Ferguson tractors has a clutch like that
     
  10. The_Josh_Bear

    The_Josh_Bear Full Access Member

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    Yep just found out the hard way that my brother's Volvo S40 2006 has one, and basically every manual Volvo has had one since a long time ago. Doing research it's basically a Euro thing so BMW, VW, Volvo etc... all dual-mass.

    But the LuK single mass for my pickup has less pedal effort and just as good of feel as the DM ever thought about having before it started slipping. So I've no idea why they worry about little gasser engines with these dumb 3x more expensive FW's. I guess for all those people that can't drive a stick it makes it more idiot-proof.
    LuK makes most of the DMFs for gassers, too.
     
  11. IDIBRONCO

    IDIBRONCO IDIBRONCO

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    Which makes sense on our trucks since I think the company that builds the ZF transmissions is located in Germany. I may be wrong on that one though.
     
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  12. Scotty4

    Scotty4 Supporting Member Supporting Member

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    Zahnradfabrik Friedrichshafen
     
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  13. chillman88

    chillman88 Supporting Member Supporting Member

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    Gesundheit LOL
     
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  14. u2slow

    u2slow bilge rat

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    Also DMF with 6 speed in a Jeep Liberty/Nitro. Mopar V6 with a Mercedes trans.
     
  15. 79jasper

    79jasper Chickenhawk

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    It's more likely intended to take out some harmonics/vibrations.

    Sent from my SM-N960U using Tapatalk
     

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