Quote:
Originally Posted by Spartarus
If you are rolling in gear, the input shaft will be moving at the same speed, regardless of whether the clutch is in or out.
from neutral to in-gear, there will be a spin-up noise if you have bearing or synchro issues. The only time the input shaft will "spin up" is going from an extended roll in neutral to being in-gear, or rolling from a dead stop. Otherwise, it will always be spinning.
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I think perhaps I wasn't fully clear in my explanation, though it's possible I'm still misunderstanding something, as I'm not yet an expert in these things. As I understand it, if my car is sitting still, clutch OUT (not depressed), with the transmission in neutral, the input shaft will be spinning along with the engine. If I clutch in, this disconnects the engine from the input shaft, and it stops spinning. If I then release the clutch, the engine is again reconnected, and the input shaft spins up again.
In my case, I hear the whine when the car is sitting, clutch out, in neutral. I press the clutch, and the sound goes away. I release the clutch, and the sound "spins up" along with the input shaft.
Also, when I shift from 1st to 2nd, the input shaft abruptly goes from spinning at 5k to spinning at 3k RPM. I can HEAR this in the form of that whine abruptly spinning down in a similar fashion as I push the gear shifter into second.
Quote:
If there is a "spin up" noise from clutch-in to clutch-out regardless of whether you are in gear, I can explain that phenomenon based on a nearly seized throwout bearing, as it begins to spin in relation to the clutch fingers, dragging against them because the minimal preload is insufficient to keep a dying bearing spinning, but the preload is sufficient to create noise against the clutch fingers. That theory can be confirmed easily; pull the trans and look at the TOB.
Otherwise, gear whine under load is usually not bearing related. It is usually related to gear alignment. If you have worn out some of the tolerances in the transmission under hard driving, whining will start to emerge. It is not necessarily a bad thing, as it doesn't necessarily indicate harm being done, just an increase in gear lash, or decrease in bearing preload. Problems of helical gears. Internal bearings going bad in a transmission don't whine. They sound like a blender full of nails.
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Unfortunately, I am not in a position to easily pull the transmission (in fact, I've never done that before.) What you are saying makes sense, but I would think that I would get at least some sort of noise with the clutch depressed, if the throw-out bearing was failing, no?
Also, if it's the latter, then that makes sense too, and I'd be totally okay with it if it's just a result of the transmission being "broken in", but as I said, I doubt it is a case of gear whine, as the sound appears to be independent of the actual gears in the transmission.