Thanks to all
I have a 55 chevy car ls3 with 4l65e trans, ecm and tcm are from 2005 corvette vin 1G1YY24U855108969.
Have been able to tune engine with no problems,
my problem is the trans shifts way to soon, 4th gear at 20mph. when looking at trans data with my snap on verus, it shows 158 mph when actual speed is 45mph, Dakota digital dash reads properly as well as ECM, just not TCM, when in the efi-live trans cal for the speedo there is a check box for corvette, transaxle etc, when I uncheck it and apply, close the box and flash pcm.
Then I go back in, and the change did not stay, the box is checked again