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Discussion Starter · #1 ·
Need help diagnosing a noise! Only occurs above
75mph when decelerating; any touch on the throttle to accelerate or balance and the vibration is gone. It's also more noise than feel,
and is from the back half of the car. Happens on straights and corners. Here's what it isn't: tires, wheels, wheel bearings, bent half shafts. Haven't found a bad u-joint, and anyway shouldn't one be bad at all speeds? Was thinking either driveshaft or differential mount. Anyone had similar problems?
 

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Discussion Starter · #2 ·
> Need help diagnosing a noise! Only occurs
> above
> 75mph when decelerating; any touch on the
> throttle to accelerate or balance and the
> vibration is gone. It's also more noise than
> feel,
> and is from the back half of the car.
> Happens on straights and corners. Here's
> what it isn't: tires, wheels, wheel
> bearings, bent half shafts. Haven't found a
> bad u-joint, and anyway shouldn't one be bad
> at all speeds? Was thinking either
> driveshaft or differential mount. Anyone had
> similar problems?
You can't rule out u-joints because you can't find it in the static state. Sometimes you have to unbolt the u-joint and twist it around to feel it bind. At that point you might as well replace them since you have them unbolted. They run about $25.00 each. What you are describing is a vibration or noise that only occurs in a torque-off state. Could it be that the u-joints are sloppy enough that they vibrate only when you aren't into the right-side pedal?
 

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Discussion Starter · #3 ·
I had this same problem a week ago. One of the bolts on the driveshaft to the diff. came loose. Just get some locktite and tighten them up. The more you drive it w/o tightning the worse it will get ... you will start to notice vibration at 70 then 65 and so on. If you wait too long you will feel it all the time at high speeds.

R.J.
 
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