I agree Josh. I have driven a lot of fast Duramax's. Some of them needed to be in 4X4 on a road test to handle them. 600 HP in a Duramax will not stay even close to me in the Hellcat. At 70 MPH, if I drop a gear it will go sideways at WOT.
I will be retiring at the end of this month. My wife has cancer and I need to take care of her. I am also going to need an operation after that and it will lay me up for a while.
Evan at Elevated Ingenuity will be taking over as the new owner. Shop will be in good hands and my crew is staying...
Put a professional scanner on the truck. Go into transmission data and pull up turbine speed sensor. At a stop it better read 0 RPM's. If not, your dprag is gone bad in the converter. Is it pushing through the brakes? If not, disregard my info.
Get codes with a Tech2. I don't know if any other scanner is good enough to get the codes. List codes in the order as they appear on the screen. Very important.
There are shifting problems with the new 10 speed along with GM and Ford. Some of the shifts are so hard, people are worying they will brake a drive shaft under tow. The law suits are starting big time.
Buy Evans kit. You won't need hard parts at 600HP. After a few years you will need a refresh with new clutches and billet parts for 1K power with a restall converter.