Automatic Transmission makes a ringing noise in gear as the truck moves and in neutral the noise stops.

 

Have you crawled underneath to look around yet? Is it only when the truck is moving (even in neutral)? I wonder could something be contacting the driveshaft as it turns. Perhaps a bad u-joint?

 

^^^ Agreed....I had a heat shield for the muffler fall on to the Drive shaft & made a kinda a ringing noise. But it can like a bad/ dry U-joint to brakes hanging up.

Just gotta crawl under it and look a round a abit.

 

The ringing noise only occurs when the transmission is in gear and not moving,the noise stops as the truck moves or when the transmission is in neutral. The noise sounds like a bearing, if it was a standard shift and the clutch was in, a bad throw out bearing. Or could it be a bad #7 bearing in the transmission ?

 

I had a whine one time under similar circumstances and it was the alternator. It only whined when I put the car in drive or reverse and went away when I accelerated away. Was positive it was the transmission.