noise at higher speed with clutch engaged

Discussion in 'VW Mk4 Jetta, Golf, New Beetle, Passat TDI forum' started by blueskymine, Aug 22, 2012.

  1. blueskymine

    blueskymine Member

    Joined:
    May 18, 2012
    Messages:
    83
    Car:
    2001 Jetta TDI
    Still trying to figure this out and I've ruled out bent or unbalanced wheels / tires.

    At about 10 mph, I can feel the car sway from left to right and vice versa - it's very subtle. Not the steering wheel, the entire car shifts.

    Slight pulsing in the shifter when in gear, when applying a certain amount of pressure on the shifter, at about 10 mph (I can feel it more in 1st gear than 2nd) that seems to correspond to the swaying.

    Doubling the speed to about 20 mph seems to increase (double?) the wobble / sway, but it seems to flatten out or disappear at higher speeds.

    At highway speeds - especially around 60 mph, a very audible hum, kind of like road noise from a heavy duty truck tire. The noise decreases dramatically as soon as I let up on the accelerator pedal and especially (just about disappears completely) when I press in the clutch pedal. There is some noise in 4th gear, but loudest in 5th.

    So it's definitely seems to be connected to the transmission - when the gear is engaged.

    I feel some wobble / pulsing when braking, but only at a specified speed when slowing down (kind of like warped rotors, which could be the case) but it's not a constant wobble all the way down to a complete stop.

    I'm thinking it's not a front wheel / hub bearing, because I would think I would hear the noise at slower speeds and it would increase in intensity / volume with speed, regardless of the clutch engaged or not.

    Also, of note, I took off the left (driver side) front tire that was on the car when I bought it and when you roll the tire down the driveway, the tire is so distorted, it will not roll straight - like there's a lump or flat spot, and the wheel will not stay upright / straight. I'm wondering if the tire became this way as a result of what could be potentially wrong?

    Is there such thing as a bent axle? Is there another bearing in the transmission? What about suspension components (control arm bushings?) or something bent? Clutch was supposed to have been replaced but I have no records on when and with what. When I changed the manual trans fluid, what came out was a rusty brown color. The Redline MTL fluid that I put in helped the shifting, but the noise is still there.

    There are about 300,000 miles on the car, bought it in May of this year, noise has been around the entire time - and to reiterate, 2001 Jetta, ALH motor, 5 speed manual trans.

    Thanks for any input / insight. Sorry for the long post.
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  2. Seatman

    Seatman Active Member

    Joined:
    Jul 9, 2010
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    5,226
    Car:
    2000 Mk4 Golf Estate 1.9tdi 174 bhp
    Location:
    Scotland
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    Check for bent axles or bad engine mounts, jack up the front, put the car in 1st gear while idling and watch the drive shafts, be careful though. It could also be the tyres themselves, some are just bad for going out of shape.
  3. blueskymine

    blueskymine Member

    Joined:
    May 18, 2012
    Messages:
    83
    Car:
    2001 Jetta TDI
    With front end on jack stands, and front tires free and clear from the ground, with the engine running and the clutch engaged in first gear, the wheels turn at a good pace and I can see the motor rocking from left to right. It appears the source of the problem is the inboard CV joint on the longer axle / right side. There is a small tear in the boot where some grease is seeping out. I am only guessing, but it's possible the joint was hit by an object heavy enough to create the hole and cause some damage resulting in the wobble.

    But I could be completely wrong and the root cause is coming from somewhere else and it just appears as though the joint is the issue. But the longer axle with the CV joint in question does appear to wobble as it turns. Is it possible the joint could have been damaged enough to cause the problem?
    Last edited by a moderator: Aug 24, 2012

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