@anwat most certainly agree that I pretty much got the comp/engine part cleared up. As I said before I am going to purchase an actual GM IAC because I believe it is a touch out and is not working properly. I pulled the PROM and it appears unmolested as the rest of the vehicle. I have a thorough history and multiple first hand information as well. I have assumed it coincidence that the trans issue manifested itself as I was correcting other mechanical problems. Maybe the other problems were enough to mask the issue. Just spit balling. Always appreciate the input.
After changing the battery which was manufactured in '17 the alternator went out. This is where it gets interesting...you know that shudder we have been discussing? Gone. Completely. Driving in O/D at low RPM, which would rattle your teeth, you can barely tell the truck is running. Anyone else ever hear of this happening? Being in aviation a fault like this is understandable. Having low or improper voltage will cause faults in aircraft systems. Didnt even think about it for a vehicle. Improper voltage to the computer and sensors that use voltage reference will give faulty inputs. Honest it is like driving a different vehicle.