Hi everyone.. thanks for all the advice over the 89 240 wagon I just bought (with a radiator leak)

Though I'd field another question out-

My sister's is practically the same car, but an 88 and dark blue. She's had it for about 4 years, and for maybe the last 2 years, it would like to do a strange thing. There's a "wooooooooooo' noise coming from what seems to be underneath the car.. It's somewhere between a "wooo' and a whistle though. It's definitely a "note" though, and increases in pitch as you accelerate, and then sometimes i swear it gets lower and then scales higher, almost like an automatic transmission changing gears, but that seems to be independent of what gear your'e in. Actually, it seems like the pitch is more related to speed, though sometimes it seems louder if theres some load (like if you let off on the gas it won't do it as much)

My first thought was that it might be some gear whine, maybe in the final drive (whatever you'd call that thingy in the back, the differential?? - I'm mostly a fwd saab person, so I don't know the termonology for RWD cars). I did replace the oil in the back there once, I don't recall if that made the noise go away.

The noise DOES go away after driving the car for like 5 to 10 minutes though.. I can't imagine that the final drive heats up enough not being near the engine, but maybe it does. It doesn't seem like it's like in any danger of imploding on us, but who knows?

-Wally