Thanks all for your feedback. I have not owned it since new, but since about 50k miles. It has 140k on it now. It's been to the GM dealer probably 3-4 times for DEF issues so I would hope they would have updated it. The last time was 3 years ago when they replaced the reservoir under warranty. About 2 months ago had a NOx sensor changed. Last month the dealer in TX replaced that reservoir again, this time at my cost. I'm taking it back to my local dealer next week but expect it will probably cost me again. I'll surely reach out to GM customer service after that but that's probably just kicking this dead horse.
2011 Chev HD2500 Duramax LML