VSTech has the right info. Since VXR1000 power, control, PTT, COR and audio headed to the portable are all working, it shouldn't be anything ugly. The problem is likely in the interconnect cable that got pulled / flexed during the remount.
Do a simple continuity check on the cable for a broken wire or mechanical connection. I can never remember if your missing audio is on pin 2 or pin 6 of the DB-9, and my cheat-sheet is pinned over my bench back at the shop. Check them all.
Chances are you'll find the issue in the DB9 or DB25 cable shell. Broken wires and bent DB-pins are nor unheard of either. If you don't find anything obviously disconnected, open up the VXR1000 and check for audio from the portable and trace the path back into the VX6000.
Also, don't be surprised if you fix one thing and break another. One bad connection may indicate none of them are up to par.
Public Safety Communications Consultant and Technician, Firefighter / COML, Interoperability Crusader and Slayer of Dragons (aka Proprietary Systems)