'91 245 5sp, 283k miles. Purchased new in 1991.

Here in Sacramento it rarely gets cold, but for the past two years, when it is below freezing in the morning, I get a ground speed related whine above 20 mph.

At 30F, I hear it as I leave the neighborhood and it goes away after a couple of miles. The other day, the temperature was in the 20s all day long (record-breaking cold snap), and it whined all the way to work and all the way home.

Sound is not related to clutch actuation, or to whether I am accelerating or decelerating. Related only to speed and temperature.

Center carrier bearing is original. Actually, everything under this car, including the complete exhaust system, is original except for the clutch, the tranny, rear axle bearings, and rear end bushings.

Also, if anyone has a theory what the deep rumbling sound in the rear end is, I would appreciate knowing. Most noticable when you slow down after a highway trip. It has been doing it for about 150k miles, so it can't be anything too serious. I have even hung my head out the rear hatch while someone drove the car trying to locate the source of the sound.