Thumping noise, but appears not to be the cluch or DMF?!

Discussion in 'Mk5 VW Jetta, Sportwagen, and Audi A3 TDI forum' started by hytron, Apr 18, 2017.

  1. hytron

    hytron Member

    Joined:
    Jan 31, 2014
    Messages:
    77
    Car:
    2006 VW Jetta TDI 1.9L
    Location:
    Michigan, USA
    Hi everyone,

    I am stuck with this weird problem

    Here is some history… bought my 2006 VW Jetta TDI with BRM engine back in 2014 and strange thumping noise was coming from the transmission side especially when you press in the clutch pedal. The pedal itself would be pulsating as it gets depressed.

    Well all along I thought it was the DMF going bad, so I decided to finally replace the clutch and these parts were replaced:

    - Clutch release bearing
    - Clutch flywheel, disc, pressure plate, as an assembly manufactured by LUK. (Splines and release bearing contact surfaces lightly lubed with high-temp grease)
    - Clutch release fork
    - Release fork pivot bolt and spring

    Assembled it all together, and guess what…the thumping noise is still there!!! The clutch is super smooth , but the pounding noise starts as soon as I press on the pedal, seems like as soon as the release bearing touches the pressure plate. I can also feel the pulsation on the clutch pedal. Even if I press the clutch pedal all the way to the floor and the clutch disc stops spinning (can verify by putting it in the gear), the noise is still there, so I am really wondering what can it be???
    :bangshead

    I was trying to figure out the frequency of the thumping noise... so engine idling 800rpm = 13.3 rev/sec, so I figure if there was a off center crankshaft, that would make 13 hits per second, but seems like it is about maybe 1/4 of it? Maybe one cylinder had issues? Not sure where to start looking for problems. The vehicle drives fine down the road...


    Any help would be greatly appreciated!
     
    Last edited: Apr 18, 2017
  2. donutman

    donutman Member

    Joined:
    Oct 10, 2010
    Messages:
    104
    Car:
    2006 Jetta 5spd.
    Location:
    north lawrence, ohio
    Mods:
    VR6 flywheel --Ross Tech VCDS
    Did you replace the flywheel. The flywheel is the part that goes bad. It has a movable rotating center which usually explodes causing the problem.
    I replaced mine with the old style VR6 solid flywheel. Now have 96,000 miles on the clutch and going strong.
     
  3. hytron

    hytron Member

    Joined:
    Jan 31, 2014
    Messages:
    77
    Car:
    2006 VW Jetta TDI 1.9L
    Location:
    Michigan, USA
    Yes the flywheel, clutch disc and pressure plate were replaced as an assembly (Brand LUK purchased from idparts.com). Any other ideas?
     

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