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Noise from rear, mainly in 3rd

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Old 10-10-2015, 03:10 AM
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pjs.oregan
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Default Noise from rear, mainly in 3rd

Hi all,

I test drove a nice-looking 944 near me today and there was a grinding noise coming from the rear that was only really noticeable in 3rd gear, and much louder at constant load. It disappeared completely with depressing the clutch pedal and was much quieter with increased load (or maybe just masked by engine noise?)

The clutch master and slave definitely need replacing (clutch creeps back into engagement after about 15s of depressing the pedal) but the owner says it's been looked at by a clutch specialist and they said it was definitely only the hydraulics and not the clutch itself (can you know this for sure?)

ATM I'm hoping it will just be a matter of changing the trans fluid as the owner doesn't seem like the most mechanically inclined, and almost certainly won't have done it in the 6 years he's had the car.

What else could it be? Clutch? Torque tube bearings? Is there any way of checking these for sure?

Would greatly appreciate any help, cheers.
Old 10-10-2015, 04:16 PM
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Noahs944
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The feared torque tube bearings perhaps?
Old 10-10-2015, 11:26 PM
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odonnell
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It could be the ring and pinion mesh, the bearings that support them get worn and they don't mesh right. Mine wails like a buzzsaw when I'm engine braking.
Old 10-11-2015, 02:26 AM
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mel_t_vin
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Originally Posted by Noahs944
The feared torque tube bearings perhaps?
Probably not...he said the noise "disappeared completely with depressing the clutch pedal". And, he said the noise was "only really noticeable in 3rd gear".

I suspect it's in the gearbox, probably something to do with the wear or alignment of the 3rd gear cluster. Hopefully, Kevin will join the discussion and provide a more accurate, detailed, synopsis.
Old 10-11-2015, 04:22 AM
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pjs.oregan
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mel_t_vin, that's what I was thinking - unlikely to be clutch or TT if it's only a certain gear at certain load. Particularly wondering if anybody has experience with something similar (and if it requires a trans rebuild / replacement )
Old 10-13-2015, 01:06 AM
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mel_t_vin
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Strange...as the 1-2 shift is the most common, it's usually second gear that starts acting up due to a worn syncro ring or chipped teeth from speed shifting.

Pretty sure if this is syncro/gear/fork-related, the box will need to come out/apart.

Is this your only car? You can always look for a good, used, box for $400-$600.



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