I have a shower tower with a seat. The diverter has failed and I would like to remove it. Facing it, the knob turns the lower 180 for temperature and the lower section pulls forward for water volume. It DOES NOT have a set screw. I have looked with a flashlight. How does it come off?

More details please! I need the brand name and model number of the valve. Can you post a picture? Has the diverter knob have a cap? Back to you, Tom