I'm surprised that someone knowledgeable in this hasn't spoken up yet. I always wonder when I see someone use the term FWD, if they mean 4 wheel drive or front wheel drive. As far as I know GMC's four wheel drive (4wd) and all wheel drive (awd) vehicles are flat towable, but check the owner's manual to be sure. Basically if all the wheels can be powered it can to flat towed. But if it's front wheel drive, it must be on a dolly with the front wheels off the pavement or trailered with all the wheels off the pavement. The difference is the transmission, and from what little I understand about it the front wheel drive vehicles tend to pump the oil out of the transmission while pulling it down the road thus damaging the tranny and even catching on fire at times. Hopefully others will speak up that have a better understanding of the reasons and differences. I go by what the owner's manual says.
Steve & Nancy
2005 Itasca Sunrise 33', W20 Chassis, Ultrapower, Henderson Trac Bar
2012 Chevy Captiva Sport AWD, ReadyBrute Elite Tow Bar, Blue Ox Base Plate, Protect-A-Tow