I changed the oil in the Sierra yesterday. I decided to check the ATF level while under the hood. Engine was still warm, but not operating temperature hot. The fluid registered well above the hot mark on the dip stick. I got a little concerned and decided I would check it again today cold. The ATF still reistered well over the hot mark. Should I be concerned? This is the first time since I bought the truck new that I have ever checked the level.