Hello, this is my first post to the forum and it looks to be very informative so maybe you guys could help me out. My truck is a '03 6.0 with the automatic. Here is the problem. I was driving through town tonight when I noticed my tow/haul light was flashing and the temp guage was pegged in the red with CHECK GUAGE lit up beside. This scared the piss out of me so I pulled over and shut the truck off. I set for 10 minutes and take back off. It's still doing it and its shifting way too hard. I hadn't be hot roddin it just driving normal. I make it back home and let is set for an hour. I went out and started it up and everything is fine. I check the fluid and its right on the money and it doesn't look like its been in there long. I've had the truck for 3 months and I've not touced it other than oil, cai, and a turbo back exhaust. So I go down the road and the temps are coming up like they normally do then the guage shot back up and that light is flashing again. Weird part is it shifted perfect on the back home. From what I've found on here is that I need a new sensor of some kind. Is this right? I also read where tuners can mess up trannys but I don't have one yet. Anybody explain to me what I need to do?