Not cost effective, but possible. Alli conversions require, along with fab work, a stand-alone TCM. 48RE swap is easier but still$$$$. You’ll spend 5grand easy just for a good trans+ all the labor and parts. You’ll recoup $2-3k on the manual if it’s a 5600 not a 4500. Thought all 04s were 6 speeds....
I like my toys and vehicles and tend to get attached sometimes, but there’s enough nice pickups out there that finding a comparable auto truck and selling the stick would be cheaper easier and less issues that are inevitable with one off custom work.
You could sell that truck for more than the cherry 2nd gen dually I posted below.
