I purchased my truck here a few months back with a lifetime warranty. I was notified during this oil change and tire rotation that GM recommends a fuel system service around 30K miles and that they could do it for another $169.00. I asked the gentleman several times if I had this done somewhere else for a much cheaper price would it affect my warranty. He was very hesitant at first to say that it wouldn't, but eventually said it would not affect my warranty, just need to keep a record of it. Communication concerning this warranty from the time of sale to now during services has not been very clear and concise. Communication with the customer in this regard could be much better. Other than that, the service department is very friendly.