The difference, in my opinion, is primarily marketing. The marketing would have you believe that GMC is a little higher assembly quality than Chevy. Thus the motto, "professional grade." Apparently enough people believe this, including the salesman I talked to, that GM is able to charge more for GMC than for Chevy trucks.
If you compare option per option the Chevrolet and GMC trucks are priced the same. The difference comes in how they are ordered and the option packages.
Currently the differince is mostly cosmetic. The box, fenders, hood, grill and all associated parts are different. Cabs are same. Romors have it they will be more unique with the new body styles coming next year.
Chevrolet and GMC are built in the same assembly plant by the same workers and there is no difference in how they are made. The same worker who checks quality on a Chevy does it also on the GMC. To the plant workers there are all GM trucks, they only become Chevrolet and GMC when they are on the dealers lot.
2009 Cadillac CTS4 AWD Performance Sedan
2012 GMC Sierra AWD Denali 6.2L
elcamino, you need to check your sources on pricing. I got my information on Chevy vs GMC prices from a salesman, as a potential buyer. I'll take his word on it.
Of course they are built in the same plant by the same workers, I only explained the marketing. If you look at the wording I used, I never once said I believed it, just that enough people believe it to pay more for a GMC than for a Chevy.
ok, I just checked prices on the chevy and gmc websites. For the silverado vs sierra, the base model is the same price. For the Traverse vs Acadia, the GMC is more for the base model. So some models are the same price, and others are different.