Today when I was leaving work for lunchbreak, I drove to the edge of the parking lot and stopped to wait for traffic to clear. When I came to a complete stop this extremely loud sound started. When I put the car into park it went away. The sound is really hard to describe but I'll try. It was a mechanical howling sound but it was a very consistent sound (it didn't oscillate or have any rhythm). It sounded almost like an airhorn but a lower tone, or the sound of a bus coming to a stop(that loud deep squeal the brakes make). It sounded like it was coming from the front passenger side of the car. But anyway I put it back into drive and it instantly went away. So I went on my way. When I got to the restaurant and stopped at the drive thru it came again. When I rollled down my window to order, the sound was extremely loud and sounded like it was coming from underneath the car. This time shifting didn't make the sound go away so I shut it off and restarted it and the sound was gone and didn't come back.

The car drives perfectly fine otherwise.
It was also really wet today in jersey, lotta rain maybe relevant idk.

 

I got nothing but I'm curious to see where this goes.

 

Forgot to give my car info.
03 Monte SS
138,000 miles

 

New symptoms today after extended driving. It would hang between gears 1 to 2 and 2 to 3. And it sometimes would have a slight jerk when accelerating from a stop. Also I checked the fluid and its a pale brownish red color. I'm thinking about doing a pan drop and filter change and see what happens? good idea?

 

It looks like the Okay one

 

Hears a wild guess....

It could be a vacuum created in the uim...
Possibly ... sign of the upper intake starting to fail...
Or it could be a bad vacuum line somewhere that's collapsing from age.


I had that similar sound just before mine failed...
But mine is a 3.8

Like its starving for air.. sort of a weird hum.

Otherwise...
I'm drawing a blank...
How about a sound bite/video?
That may help to clarify the sound.


Heres another guess...
Maybe theres pressure building up in the cat?
Maybe it clogs up once its at running temp? drive it..get it warmed up to normal operating temps and take a look at the cat..if its glowing red... That's more than likely the problem.

 

That's the thing man it only happened when I made this post and it hasn't happened since. There was a ton of rain that day, that's why I'm thinking it had something to do with it. I'm thinking now maybe the brakes were sticky from the rain so the ABS reacted to that. But I was at a complete stop. Maybe axle spin? I'm not sure. The tranny problems I think it just needs a change I'm hoping

 

The car was cold I just started it and also it was replaced two years ago or so.