OE parts supplier 2006 Express 6.0L 480LE
 

Hello cousins across the Pond.
I need (and no doubt will need more!) some parts for transmssion (drive/flex plate), engine (poss head gaskets) and I also need the heater distribution control rotary dial.
I don't need shipping to the UK necessarily, as I have a buddy who comes across a couple of times a year, so can bring parts back for me.

Ideally a website or supplier that can show the exploding diagrams of all parts would be best. i've tried GM Parts Headquarters for the heater control rotary, but it doesnt show the dash switches and rotary layout.

Thank in advance

4l80e