I have a 73 c10
With a dbc 5.3
It has a 4l60e in it
It has the TCC hooked up
Two things first
The Speedo when connect to my WiFi dongle through my phone is off by 10-15 MPH
Second issue is the truck won’t coast?
I let off the gas and it acts like indown shift?
Is this related to my Speedo issue or something else?