I used a sender 4PAC from jagsthatrun.com ($104). I wired it as another person posted but found the speedometer cable drive gears in the turbo 400 made the speedometer inaccurate. Rather then change gears I found that Summit sells a universal speedometer calibration unit made by Dakota Digital (DAK-SGI-5E) for $80 that did the trick. I cut the connector to the VSS (yellow box) and wired the input from the sender to the box then used the original circuit out to the speedometer. A quick drive using any app that tracks your speed and a passenger to change the calibration and it works great.