I had some buzzing noises coming up from a shifter area for quite a while.
Recently while doing tranny and tc work I decided to replace the shifter cables with teflon coated from 2005 model and look what I found.
A little spring has some plastic sleeves that look and feel like PVC.
Over the years plastic hardened, lost an elasticity and chipped of causing metal to metal contact with the metal pin. Metal-to metal + vibration = buzz.

Changed the spring, shifting is smooth, no more buzz.