Synthetic oil thread in my sig.
My engine is very quiet, in my sig also I recorded it.
Redline oil has helped most of the people who use it about 10 at last count but not all. So far 2 and maybe a 3rd coming have not had success running it, and Motul is a Redline clone and should help also. Other brands have helped too, Amsoil SS and Penzoil Ultra. Seams like Mobil One is hit and miss. For the reason these oils may help read the synthetic oil thread. What you are experiencing is metal to metal contact in your lifters usually when you first start your truck. I am sure you have heard the ol saying most engine wear happens at start up. Well, to make it worse, we use a very thin oil, so while it does lubricate very fast, it has the weakest film strength and drains thoroughly when hot and sitting. So a quality oil provide better film strength by up to 40% at operating temps and additives like molybdenum and some oils like redline also have greater zinc numbers. My engine sounded like a meet grinder and now is very smooth, and all I did was change to Redline oil. Why redline or Motul? They have the most Moly 880ppm, and group 5 oil base which has the greatest film strength at operating temps, and high zinc are among the reasons it is my choice. If you do use any synthetic, get a synthetic filter like royal purple and you can run 10k miles easy.
I was exactly like you, my hemi tick came very early on and got really bad fairly quick, to the point it sounded more like a knock then a tick. If your tick.knock is happening right at startup, it will likely get worse and the likely cause is the lifters. If it keeps happening the first thing I would do is take it to the dealer and see what they say. Most will punt and say normal, and if they do at least you will have a reciept of the problem. Then consider using a quality oil, I can't stress how important it is to use any synthetic over a blend or even worse straight conventional oil. It is because of out engines and the thin oil we are forced to use to run the MDS.
You can also get a catch can and run a upper cylinder lube with your gas like lucas or marvelous mystery oil. However, oil is much more effective but running a catch can will keep your oil cleaner and lucas does make my upper cylinder quiet is some of my cars.
I never heard of running ATF in the gas and wouldn't do it personally. Many people used it as an engine flush in the oil because ATF has a lot of detergents. However, if you are running Redline or Amsoil and you have a catch can or a good working PCV, you will never need to run atf for a flush.