Hearing a noise at idle when truck is stopped. Feels like slight vibration and goes away when truck is in neutral (Noise comes and goes) .... Are there any chronic issues with the torque converters? Sorry all...too many years with a straight shift tranny....me an automatics just don't seem to get along.

 

possible the inspection cover is giving you that vibration..

some people on the site here have had good success prying the edge away were it can vibrate against the housing.

also check for exhaust heat shields being loose and vibrating.

 

Push and prod things while it is idling to detect it.