4L80E Shift Enhancer
This device simply taps into 2 wires near the PCM on your 6.5L diesel and provides 3 different shift firmness levels by altering the line pressure signal going to the transmission.
It's great for allowing you to firm up shifts when desired while offering the choice to go back to stock for normal, relaxed, driving.
The positions are as follows:
- Level 1 - Firmer
- Stock, or whatever settings are in the PCM/Tune by default
- Level 2 - Firmest