Bath tub leak

I have a two year old home that is equipped with Moen fixtures. My combination bathtub/shower faucet has begun to leak in my second bath. After running the bathtub or shower the water continues slowly drip out. The faucet has one of those pull up knobs that is used to activate the shower. When I look up the faucet it appears the knob is not stopping the water from coming out after the water has been turned off. Do these knobs wear out? Or is the problem somewhere else? Please help!

The diverter (the thing you pull up to switch to the shower) wears out over time (is this on the tub spout?). Sometimes they stick up and it will continue to drip for a fair amount of time as the water in the pipe from the valve up to the shower leaks out drip by drip. Normally, when you shut off the water, they open up and all of the water in the pipe flows out fairly quickly. If water keeps dripping after the diverter and riser pipe to the showerhead has completely drained, then your valve is leaking. Not sure about the warranty, but many have a lifetime one - check with Moen and they'll probably send you a new cartridge for it. My unprofessional opinion.

Thanks for the response. What you say makes sense. I'll check with Moen.