The 2013 GMC Savana has a 4-speed automatic.
The 2013 GMC Yukon has a 6-speed shiftable automatic.
The 2013 GMC Acadia has a 6-speed shiftable automatic.
The 2013 GMC Terrain has a 6-speed shiftable automatic.
The 2013 GMC Savana-Cargo has a 4-speed automatic.
The 2013 GMC Yukon-Hybrid has a 4-speed automatic.
The 2013 GMC Sierra-1500 has a 4-speed automatic.
The 2013 GMC Yukon-XL has a 6-speed shiftable automatic.
The 2013 GMC Sierra-3500HD has a 6-speed shiftable automatic.
The 2013 GMC Sierra-1500-Hybrid has a 4-speed shiftable automatic.
It's worth about $13,000. See quotes at http://www.edmunds.com/gmc/sierra2500hd/2006/index.html
The 2013 GMC Acadia runs on regular unleaded.