Gear stripping ag13a020

[sheppsr]

We've have been struggling with a single 3way valve actuator at our facility stripping a tooth. It seemed to be a bad batch of actuators but the new shipment we received is doing the same thing. I thought I found the culprit (the metal plate the drive motor mounts to was rotated clockwise decreasing the amount of mesh between the gears) 2 days ago, but it failed again. We've resorted to gluing a piece of cork gasket material to limit the travel of the arm in the closed position. This is on a 2 pipe FCU currently running heat. Boiler temp is currently in the 160F range. The 3way valve stem itself moves freely. Is there anything else we should look into before resorting to replacing the whole valve assembly?