I am following helpful posts on this forum to replace a failing tub diverter. Our spout does not have a set screw so I have deduced that it is a threaded model. I have removed the caulk and used a pipe wrench. I have used a fair amount of torque and it doesn't want to break loose. I just don't want to shear off the pipe - not sure if I could do that. Just would rather not turn a small fix into a giant problem. Is this normal? Just thinking that scale and corrosion might have locked things up a little. Should I just give it 100% or is it time to call in a pro?