Pro's:

While snaking a tub drain, I discovered a larger problem. While hand snaking, the Gerber W&O broke free where the horizontal arm threads into the brass drain bottom. Seems due to some corrosion at the threads. I see broken threads on teh end of the arm, and got a tub that was 1/3 full of tenants' shower water empty into the kitchen ceiling below.

From below, I have "reach-in" access to one side of the drain, as from above via the access panel behind the tub. Do I need to replace the entire W&O, and which would you recommend for tenant use? (I suppose I would have to replace the whole thing since I can't see the remaining threads in the fitting from the side view.) This connects to glue-in PVC trap, and I do have access to the PVC drain line.

Thanks.