Clamshell stuck- roof not working
 

My roof got stuck in the closed position. Clamshell tried to open slightly on one side but no movement on the other side. Could hear motor trying to operate.
Only access via the cabin and local garage undid the 19mm bolt to remove boomerangs and linkages on both sides. Clamshell and roof will now move manually.
Cables unclipped from the motor to help with diagnostics. The internal cable on the good side rotates easily inside the outer sleeve. The cable on the bad side does not seem to rotate.
So, is this likely to be problem with the transmission gear failure?
And is removing and opening up the transmission the next best step?
This is a bit outside my comfort zone...
Any assistance will be much appreciated!

My linkage bound up so I unhooked everything for the motors and struts for the top, essentially converted it to manual. Never looked back. I can raise and lower my top in seconds now. FWIW