I have a 2003 6.0 with 4l80e DBC swap in 89 FS. It will not up-shift until almost redline. The only things that seems to affect it and get shifting closer to where it should be is if I change VSS pulse/revolution from 40 to 20. Trans is an early 90's 4l80 with newer harness and solenoids. I've tried multiple tunes and PCM's (DBC, express van PCMs from 03 and a few 03 Silverado PCM's with the IAC drivers). Any ideas on what I can try next? I am using OS 12592618