modem data not working on custom rom need some help

Hello all long time xda member new lg g3 member
Lg g3 d851 t mobile kitkat rooted

I hAve an issue
I want to go to cyanogenmod 12.1
I can flash it but everything i do to get the radio working comes to no avail no data etc,
Could one of you shed some light? Maybe a new modem or flashable zip I'm totally missing?