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-   -   Mysterious noise from rear of car (https://www.miataturbo.net/general-miata-chat-9/mysterious-noise-rear-car-66886/)

2ndGearRubber 06-29-2012 07:51 PM

Mysterious noise from rear of car
So, driving to work today, my 99 made a new noise. It sounds like a high pitched grind of metal, or a very high frequency heat shield rattle.

It happens, generally, at times when my OEM torsen diff would begin to lock up; or during decel, when going from a high rpm in a low gear, to zero throttle in the same gear.

I checked the axles, they both have very slight play, moving from the diff towards the wheel. The play in this plane of motion is very slight, less than 1/8 of an inch, and slightly worse on the drivers side. With a twisting load (with my hand on the axle between the 2 CV joints) the right side has no play. The left side twisted slightly on my first wiggle, but I have been unable to replicate this play.

I'm changing the diff fluid tomorrow, the current fluid has 40k on it. My concern is about an over-rev I had about a week ago. I put the car into 2nd at about 60. I know, :facepalm:. I got the clutch in before it fully grabbed, but I'm sure the engine got close to 8k. Again, :facepalm:. I immediately changed the oil (it was a little low, Castrol 10-30 high mileage, about 2,000 miles on it), and the trans seems fine. It shifts well, and the clutch still feels okay.

Facts about my car: 1999/120,000 miles. Stock trans, clutch, flywheel, diff and axles. Rear sway bar is stock (so I doubt the gas tank heat shield is hitting it), enthuza cat back (the very narrow "XR", so I doubt that's rattling).

Should I assume my axles are going out? Or could the diff be at fault? I've never heard of a Torsen going bad. :dunno: A shop I went to about a 6 months ago (My shop was too busy on my day off to lend me the alignment rack) said there was play in the axles, but they also said my brand new 949 endlinks were bad, so I didn't really believe them.

Thank you for any input.

Faeflora 06-29-2012 08:44 PM

Don't fear overrev
I have reved to twelve thousand
Motor has strong teeth

2ndGearRubber 06-29-2012 10:08 PM


Originally Posted by Faeflora (Post 897253)
Don't fear overrev
I have reved to twelve thousand
Motor has strong teeth

Yes, but my BP4W is 100% stock internally. I doubt anything other than some serious valve float occurred. I'm a bit overprotective/paranoid about my car. I'm always worried about some problem or issue that I shouldn't be.

This issue, is serious though. And I need to figure out what to do before I just start buying axles and ----.

olderguy 06-30-2012 07:24 AM

Check your brake shields.

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