No previous symptons - hot afternoon, just leaving the airport. I turned on the a/c once I reached the highway. The whole truck lurched a tad -I presume from the clutch freezing - and I received only hot air. Shutoff the a/c. Blower was fine. When I tried the a/c again, nothing but an almost grinding sound. Took it to the shop (locally run, real honest guy) and he had that 'this is going to cost you' half grin on his face. He had done some research and found out there was a defect in the a/c system design for the early 2001s which eventually led to trapped oil and compressor failure. Of course, you get the standard canned response from GM- isolated case my backside. I have rear a/c on mine and the entire system piping, compressor & condenser had to be replaced. $2700 and about $1800 of it was parts! I swear those refrigerant lines are copper but they're priced like platinum. I think I can buy new a/c for my house with less money. At last check, the new system is working fine...