4l80 swap/ segment swap issues

Probably just something simple im missing, but figured I would reach out before messing something up.

The truck is a 05 silverado 1500 4.3 4x4 manual trans. Swapped in a 5.3 4l80, but kept the 4.3 ecm to retain DBC.

The issue is i cannot get the [PRND321] to display lights on the cluster, confirmed that they do work by swapping to the donor trucks ECM (02 silverado will also include this tune file). I did perform a segment swap from a chevy express i got from the repository. Engine runs wheels do move when put in drive just no gear indicator lights present. will the truck drive like this?

OTHER INFO
cluster, steering column, and trans all from 02 donor truck. 5.3 does have a TSP stage 4 high lift truck cam and circle D converter. i did repin the ecu harness following https://lt1swap.com/cable_conversion.htm this document.


TUNE FILES
1. factory 4.3 tune
2. donor truck factory tune
3. the express i performed a segment swap with
4. the current tune that the truck runs on

Why not try using the transmission segments from an '05 2500 4L80 truck instead of a van? Something from the same platform is more likely to be able to run all that platform's features.

I choose the van because they retain DBC, but you make a valid point. i just segment swapped the trans and trans diag. no difference, should i keep trying different OS's? Im trying to be cautious as it is listed brickable to write entire.

Figured it out!!!! I was right about missing something simple.... Went ahead and segment swapped the speedo and system as well, cluster now displays lights. lesson learned