you need to go online at acdelcotds.com, register and pay a 2 day sub for 55 usd. need a windows pc os 7 or 8, interenet explorer 11 java 7.67 from their site, a passthru device such as the autel maxiflash pro etc.  this seems to be your first time flashing obviously so read a lot and watch a couple of youtube videos before you decide to do it, can ruin a module very easy specially on this vehicle where ecm and tcm gets flashed simultaneously.

Today I replace a TCM on a Pontiac 2006 Torrent. The procedures on this video are the same for the replacement of the TCM Module.
https://www.youtube.com/watch?v=bc7bRzVIb0E

 Hi Dear,, thx for sharing info i was going through the community and chekout this ,, one question, is the autel J2534 pass through device is authorised to use with AcDelco and Witech??