So i have swapped my auto for a t56. I turned off all the transmission dtc's and changed the tune to show manual transmission. I corrected the speedo and flashed the computer on the truck. For some reason the truck keeps going into limp mode with/in seconds of cranking it up.

What am i doing wrong? I have attached my tune if someone could take a look at it.

I appreciate any and all help.RS_1999_Tahoe_t56_0400_transdtcsoff_2_0000.tun