I just had a service done on my 2016 3500, DRW 4X4 truck at a dealership. I have the Duramax with an Allison trans. The dealership filled the trans to the full cold line on the stick. This seems a little low to me. I do realize this is probably the recommended fill point, but even when the transmission warms up the fluid level does not change, let alone expand to the full hot line. Am I just being paranoid? By the way I do tow a very large horse trailer with this truck, and I don't want to have an issue. Thanks for any advise.