[CarreraS2]

OK I'll fess up and admit this is for my '86 BMW, but the issue is likely applicable to any manual tranny, including a 911.

I get a really loud gear whine/howl, sounds like it's from the transmission (manual 5 speed).

It is most loud at light loads in the 2000-3000 rpm range. For example, cruising at 2000 rpm, need to accelerate a slight bit, give it a tiny bit of gas. It will howl/whine as the car slowly accelerates through the rev range.

When you let off the throttle, it's still there, but nowhere near as loud.

If I'm driving in gear kinda coasting (like very slight throttle, so little the car is very slowly slowing down), the noise is gone.

Put the clutch in, noise goes away completely.

Put it in neutral, noise goes away completely.

Started around 10K miles ago, increasingly getting louder.

The trans has probably 160K on it. I put it in the car when it had around 125K on it, and it worked fine at the time. Replaced the clutch, TOB, and pilot bearing at that time. So those components were all new less than 40K miles ago (although I'm not ruling those out because of that).

Shifts fine.

Any ideas?