[breshears1996]

I got a 05 6.0 awd it's shifting fing manually but when in drive it's not shifting on its own

 

[EXTeroceptor]

Look to the PCM (powertrain control module) or the various sensors, especially the VSS (vehicle speed sensor) and TPS (throttle position sensor). Check all the associated wiring as well for any chafed insulation or broken wires.

 

[EXTeroceptor]

Also, you'll definitely want to scan for any codes. If you have a scanner that is capable of viewing transmission data that would provide very helpful information.