I have over 150K miles. Last year the knocking started, but disappeared when I took it to the mechanic. It has recently gotten more noticeable. The "knocks" seem to be coming from underneath the car and increase with acceleration. Could this be from the flex coupling? If so, what are the torque specs?

Knocking from the suspension or the engine or the trans. Could you be a little more specific.

The flex disc uses a lock nut on each bolt. I just feel the tightness. I don't feel it is necessary to torque these bolts.

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Benzmac:
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Dear Benzmac,

I don't think it's the engine or suspension. My best guess is the drivetrain. Of course, my instincts usually point me in the direction of the simplest cause, first. Hence, my suspicions on the flex coupling. The rear one seems to be in good condition. I will inspect the front one this weekend when I change the oil. So, will a worn out coupling produce such a noise? I don't know if this will help, but the noise only comes out after I've driven the car for some time. This never happens on my morning commute.

It could be, but then again it could be a number of things. I have seen them cause strange noises though.
Good luck.

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Benzmac:
ASE CERTIFIED MASTER AUTO TECHNICIAN
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Dear Benzmac,

I surfed to older postings looking for similar reports. I found one posted by Altan 6/10. You recommended that he check the flex disks. On 5/19, you told Corey D that you suspected his differential. Well ... for my wallet's sake, I hope it's the disk. Thanks for your help. I will let you know how it turns out.

I checked the couplings, front and rear, and they seem to be in very good condition. No wear, no cracking. If the noise is coming from the differential, what could be wrong with it and how do I go about exploring this possibility? Appreciate the help.

There is a slip joint in the center of the driveshaft. It is there to allow some movement of the driveshaft. If it is a little loose(the lock nuts) it will clunk a little.

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Benzmac:
ASE CERTIFIED MASTER AUTO TECHNICIAN
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