In the past, the only way to do this was to do what is called a segment swap, which involves finding another tune file to pull a transmission segment from. Segment swaps are messy, and flat out do not work for some applications. It basically involved finding another factory vehicle with the same OS ID as your vehicle but came factory with a 4l80. The bad thing is: there are a ton of applications that never had a 4l80 option. For instance, 1998 Corvette or any vehicle that came with an E40 ECM. In some cases, segment swaps can lead to other problems. IE: shifter indicators (PRNDL) not working, or cruise control issues. Segment swaps between applications can also lead to other issues, i.e. mixing Corvette & Full-Size truck.
Not with our harness. Plug it in and GO! We also offer 4l80e swap transmission tuning, both mail order – link, and via HP tuners email tuning – link.