Just bought a used 2015 F250 4x4 with 6 speed auto and 20K miles on it. It never towed. When cruising around I occasionally hear a 1 to 2 second buzzing sound (haven't noticed it on acceleration). It's not always when the transmission is shifting but sometimes it seems its right at the end of an upshift (I think 5th to 6th or maybe it's 6th to lockup?). Seems to happen more while tranny is warming up but still happens after, maybe once a minute if I'm listening for it. It isn't loud, with the radio on I don't even think I'd hear it.

Normal? It's still under warranty but if this is a normal sound I don't want to worry about it.

 

Just a guess, but check to see if you have a loose heat shield on a catalytic converter.

 

I checked that out today, everything is tight very tight.

Anyone with the 6.2 and 6 speed auto willing to turn off their radio and listen for this to help me determine if it's normal ? It's very low in volume....but once you hear it once you'll hear it every time !