1992 240 non-turbo AT sedan > 250K miles has a growl at low speed. Owner (friend) says it's just gotten worse over the past 1-2 years. He said it's "not bad" but to me it's loud. A friend rode w/ me and immediately said "what's that loud grinding?"

Today I drove 150+ miles. It may be slightly worse after the car warms up. It's somewhat engine-speed dependent when moving but 0 noise when revving the stopped car. It's gone (or nearly so) when revving the engine in neutral while coasting. It goes away completely when coasting and is negligible above 70 MPH. It's worst under load ac- or decelerating; especially in a parking lot at 3-4 MPH.

Coming up to a stop it sounds/ feels like brakes on rusty/ scored rotors but the noise is the same if you're not using the brakes.

It changes noticeably when the car shifts which made me wonder if it was a trans bearing.

Tires, carrier bearing, u-joints, front wheel bearings, brake pads and calipers, motor mounts are new or changed out. I don't think the exhaust is hitting anything but it's not really that kind of noise. The rear TABs look OK but it's not that kind of noise either - and I've had that on accelerating or decelerating but not both.

I'm going out now to check rear emer-brake pads - but I've experienced that before and this noise is different. I'll also suspect rear wheel bearings - but I'm never had any of these go bad. And I'll look again at thew trans mount.

Suggestions after that?
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240s: 2 drivers and some parts cars