Follow up to post.

Trans problem ended up needing a new governor pressure sensor transducer and solenoid kit. I put in the aftermarket ones everyone on the cummins boards were recommending.

https://www.xtremediesel.com/sun-coa...d-upgrade.aspx
https://www.xtremediesel.com/bd-powe...grade-kit.aspx

Truck has been running great otherwise, but popped a manifold-turbo gasket on the first hard pull back in July. Minor pinhole leak. I couldn't ID where it was from at first (except for the noise) until the soot built up and I'm just getting to the point where I need to fix it. With the 2-piece manf and everything else new, I'm hoping I can just pull the back half w/turbo off and get it on the bench to replace the gasket.