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S4 GTU noisy drivetrain

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Old 05-10-13, 12:28 AM
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S4 GTU noisy drivetrain

I want to run this by you guys. Here is a video I cut out that picked up noise from the drive shaft. The noise only exists taking turns at low speeds. The diff has been rebuilt with a preload of 90ft-lb. I know these are known to be noisy with preload I just want to hear what you guys think before I start taring into the trans. This is a 1988 gtu.

Old 05-12-13, 04:07 PM
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Wow..that isn't normal at all. I wouldn't worry about the trans, its in the rear end or hubs.
Old 05-13-13, 10:50 AM
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Thanks for the reply K-Tune.
I really had nothing as a comparison, a buddy of mine has a welded diff and his wheels skip and my car has a pre-load of 90lb-ft before the wheels break. It does a good job on the track, its low speeds as you've heard that really concerns me. Last time on the lift I turned the shaft by hand and noticed that the wheels would be spinning before i hear clung coming from the transmission.
It almost sounds like the drive shaft is skipping teeth.
Old 05-13-13, 06:06 PM
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That doesn't sound like wheel break to me, at least not what I remember from my buddys welded diff. It sounds like something is scraping when you turn. Is it low speed or is it just how much you turn the wheel?
Old 05-14-13, 02:07 PM
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Originally Posted by farberio
That doesn't sound like wheel break to me, at least not what I remember from my buddys welded diff. It sounds like something is scraping when you turn. Is it low speed or is it just how much you turn the wheel?
Its only at low speeds and it doesn't matter on how big of a turn I make the sound is pretty constant. The diff has been shimmed. Could it be a slack between the drive-shaft and transmission?
Old 05-14-13, 10:08 PM
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I figured out what my problem is with the diff, it is completely locked. I remember testing the preload when I first built it, it was at 90lb, now I cant even break the wheels with my torque wrench rated at 150lb. Can the diff ever fail in locked up position?
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