Klug, On your 98 harness C1-15 Yellow/Black wire of the PCM will be installed into C2-49 of the Gen3 PCM. BUT---This is when using a factory harness. Since you have an aftermarket harness and I don't know what it does or doesn't have in it---You may want to run the two PCMs. If you ever do another one of these trucks, don't use two PCMs. It is not necessary.

Shmiet, I didn't mess with the C100 connector. I repined the stock harness for the Gen3 PCM and added 10 wires to the harness to run a Gen3 engine. All of my gauges work fine. The 4896 PCM will work.

Jeff