It can be difficult trying to make things right, on a project that has evolved in an eclectic manner, without your consultation. You have three main options for success, with numerous sub-options.

1. Add a TCM, and control the automatic transmission via this TCM. This would represent the most complex (lots of wiring to add) and expensive option. This option would also require additional custom tuning.

2. Program the E38 with a manual tune. The only options for this (given that you are using a 2007 truck OS and E38) are a 2007 Corvette (LS2) or 2008 Corvette (LS3) manual tune. This programming would need to be done initially with GM equipment (Tech 2, MDI, etc.) This option would require a Corvette APP (gas pedal) and throttle body (the 2005 to 2008 silver blade type) - which are becoming quite expensive (given their obsolescence).

3. Find a good conversion tuner to make your existing tune and equipment work together harmoniously. It seems that you can find a Dyno Tuner on almost every street corner these days – but most of these people only do “airflow” tuning. A Conversion Tuner is someone who has the skills and knowledge to address issues with the overall project, including module communication, mismatched platforms, and reconfiguring inputs and outputs as is necessary.