2004.5 Chevy 2500HD CCLB 4x4
So, the dealer I bought my truck from wanted to do a full service before delivering the truck. It was new on his lot and they hadnt been able to get it serviced when we went down to look it over. He changed the oil and put on new brakes. He said the truck threw a CEL on the after service check out ride. The mechanic said it was an issue with the turbo. Dealer said the impeller or vanes had a crack and they need a couple more days to get the part in to fix it. He said they are going to put a new turbo on at his expense. I can't find any info about cracked turbo or impeller online. Anyone ever heard of that? Dealer is an honest guy and his dealership has great reviews so I am pretty sure it isn't a line of BS. Just wondering what may be wrong. I have read about sticking unison ring, maybe that was the issue and the dealer just incorrectly quoted the mechanic?