Removing Hydropump Impeller

I seem to have hit the same roadblock a couple of other posters have in the past. I'm disassembling my pump to replace the mechanical seal and can't get the impeller off. Before I break the impeller, can anyone confirm that the HydroPump does indeed have a threaded shaft. I've put a lot of force on it trying to turn it with no sucess. The online instructions from Pentair don't specify how to remove the impeller. The only other option I can see might be that the shaft extension might need to be removed from the motor shaft with the impeller coming out with it.

Any guidance on what I thought was going to be a straight forward job would be appreciated.

Thank you.

I now have the answer to my question. I took the extension shaft off the motor with the impeller on it. Someone put it in a vise and twisted it off for me so if anyone else has a Hydropump brand pump, it is indeed a threaded attachment for the impeller. Now I can proceed with my repair and hopefully get it back in action.