This is a question about a pickup, not a big truck. Our Town Highway Dept. has a Chevy 2500 Duramax that requires DEF, I'm not sure of the year. It has had to return to the dealer on average every 3000 miles to have a sensor in the exhaust replaced. While it's covered under warranty, the time required to run back and forth to the dealer and loss of the use of the truck is costly. The dealer's explanation thus far is the truck requires #1 diesel instead of the much more common #2, that the #2 is gumming up the sensor. I'm not buying this, as this seems to be the only case of this problem the dealer has encountered. We have #2 diesel storage tanks and would either need an additional tank or buy fuel for that truck retail, both of which are inconvenient and costly. Has anyone heard any similar story to this?