LSx swap Speedo ?

[Clyde65]

I have the 4.8/4l60e in my truck along with a Dolphin electronic speedo, when I am just driving, the speedo looks pretty acurate, however when I slow down and stop the speedo goes all the way to max speed and when I am stopped hovers around 60mph or so, any ideas?

I was told by Dolphin to hook the wire from the trans straight to the speedo to see if this works, how is everyone else hooking their electronic speedo up? I have a stock modified harness( by W4M) and they provided a stub out wire for the speedo, which is what the speedo's wire is connected to. Any assistance would be great.