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Discussion Starter #1
Hi

I own a 1990 300ZX Z32, NA, 5Spd Manual, 2+2 and recently I have noticed a really bad vibration and noise whenever the revs get to 5000 or over. The car is fine until then but as soon as it hits 5000 revs I can feel bad vibrations through the gearstick and pedals and a bad noise that sounds like something is going to come flying off the car - maybe bad bearings of some sort.

This happens is all situations - clutch depressed or not and in all gears plus neutral, parked or driving.

Anyone experienced this or have any ideas what it could be? Any suggestions would be greatly appreciated.
 

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do you have the stock driveshaft?

if so my guess is going toward the center bearing on the ds
 

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If you're experiencing it when the car is parked as well, I would say bad motor mounts and tranny mounts may also be contributing factors.
 

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How many miles on the car? I would suspect a bad drive shaft too. I would replace it with 1 piece ds. I had the same symptoms and replaced mine. Allis ok now, and I can lube the U joints.
 

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It's very hard to imagine that this is a driveshaft problem if it happens when the car is in neutral, or parked.

It would not have anything to do with componants past the transmission if that were the case.

From what you said, it seems to be related to Hi RPMs rather than anything else.

Ususally in such instances the vibrations will build gradually, rather than coming on all of a sudden, as you mention.

I am no expert on such matters, but the suggestion reguarding motor mounts sounds like a reasonable one, seeing as how you are feeling the motor/transmission unit vibrating through the shift knob when the car itself is not in motion.

If it were motor mounts, the noise you hear could be other componants shaking or begining to hit each othr as a result of unintended range of motion in the engine/transmission unit.

You could take a look under the hood while someone revs the engine, and see what things look like ?? If it were mounts, you might notice an initial big twist to one side, which increases a little as the revs build ??

The fact that you feel vibrations through the pedals may or may not mean something. They are not mechanically connected to the engine, and may reflect uncontroled vibrations that are making it to the body of the car itself.

Just my take on it all,

Bob
 

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Discussion Starter #6
Car has done a little over 100,000 kms.

Driveshaft and all transmission and engine components are stock.

Thanks for all your input and help people - I'm going to spend the day today trying to figure this one out. I'll let you know how I go.
 
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