Roaring noise at slight acceleration
 

My 97 540I automatic has a loud roaring noise at slight pulling. When given more gas, or let off gas, it stops. Does it at 30 or 70.
It's loud. I've had BMW locally check it and they like the other mechanics that have looked at it say keep on driving, turn up the radio until it breaks then we can fix it.
Everything works just great.
Any of you BMW experts have any ideas?

Where is the roaring noise coming from? And did they give you any indication of what they wanted to fix after it broke? Without having the vehicle present to test, it could be a ton of stuff.

Thanks for replying Big Evil, Love Tempe too!!! Lots of cotton like old Alabama.

its from the middle to back underneath. They checked out wheel bearings, differential and tranny oil and just don't know. Can't get it to do it on rack.
Very loud, can't miss it. Rubbing roar. Checked out tires and no rub spots.

Funny how it won't do it coasting or when giving more gas, only at cruising gas amount. Stops immediately when let off gas or put in neutral no matter what speed.

Sounds like you covered the basics

I'd be looking at the center support bearing going bad on the driveshaft (it's under a heat shield above the exhaust and not the easiest to check). The u joints get old and aren't serviceable so it's a driveshaft replacement if that's what's happening. Rule of thumb if the center support goes out, don't waste your time replacing it. You'll be doing the whole shaft in a couple more weeks/months when that one fails too (and it will).

That's really about the only other spinning thing down there that can be doing it, so it's worth the effort to check.

My 97 540I automatic has a loud roaring noise at slight pulling.

Loud roaring noise AND slight pulling? Or Loud roaring noise at a light throttle position?

Where is the noise coming from? Did something change that you noticed in between it making the noise and it not making the noise?

Funny how it won't do it coasting or when giving more gas, only at cruising gas amount. Stops immediately when let off gas or put in neutral no matter what speed.

Check exhaust hangers and motor mounts. I don't remember if your year had an inertial isolator on the exhaust (basically a big weight bolted it on to eliminate resonance frequencies at cruising speeds)