Hey everybody, I'm having an issue in the final stages of servicing my 72b movement. Everything is functional until I install the automatic works. Anybody have any ideas what to look for? I've ensured all the gears within the automatic works are moving freely, the automatic counterweight winds the movement when spun, but doesn't allow hand winding while it is installed.

Kind of stuck here so any help would be greatly appreciated!

It is all about friction. There are dozens of possible friction sources: dirt, corrosion, wear, compromised geometry
1. Did you service the mainspring barrel? It could be dry inside. Hence friction.
2. Did you clean and oil the reversing wheels? No oil at all or excessive oiling will cause tough winding. Tiny friction in reversing gears, leveraged by gear ratio, will stop manual winding completely
3. Check automatic bridge integrity. Often it has cracks. As result, its geometry compromised. Revering gears must be parallel to the bridge plain.
4. Check reversing gear bearings (preferably under microscope). Wear in them will cause side shake. Even tiny angle of reversing gear increases friction dramatically. And it multiplied by gear ratio.
5. Check side shake on rotor axel.
There are more other causes too. But these are most common. And, of course, all above could be cumulative. One could add to other.

Thanks Yuri! I'll start checking through the list you gave. I'm worried it's an alignment issue