Thanks for all the great suggestions about what my problems may be. The FAQ has been great, too. The result, however, is that I am completely confused. :O

Let me re-hash all the things that I have observed, then... I'll go on a rampage replacing stuff! >:]

740GLE sedan, AW70L (replacement 100k ago). I was under the tranny the other day, and no visible leaks. Fluid level seems high (though I don't think I'm checking it right). Fluid is probably overdue to be changed, but is still red.

In-town: just noise. As the RPMs get to around 2000-2500 (just before the shift point for my light foot) there's an intermittent sound like fingers on a chalkboard coming from under the car. It's pretty loud (reflects off walls and other cars). No appreciable shimmy or loss of power, or shudder. Just noise. If I lay on the gas, the sound will return at any RPM under 3k.

On the highway: At speeds above 45, in 4th gear, if I try to pass or accelerate moderately, the whole car will shudder. As I reach a certain point in the travel of the gas pedal, I can feel it come on, and if I let the gas back out, past this (fixed?) point, the shudder will fade. Kicking down to third will eliminate the shudder and I'll accelerate smoothly (and fast!).

Am I dealing with two separate driveline/tranny issues? Fuel delivery? Ignition?

Differential's fine, too. I checked fluid; looks ok, no leaks.

Thanks for the help. This one has me stumped.

Ari