When I bought my truck, it just said "Transmission upgrade" the seller couldn't say what it was.

The only thing I can figure out is it locks up in overdrive almost like listed on MM3 tuning (torque converter lockup in 2nd, etc)

How can I figure out what's been done to it?

Will appcar/alfaobd be able to see if it's software, and what do I look out for?

The ultimate question, is, is it a 68RFE or 48RE?

It's a 2006 5.9L Cummins.