Someone please help, Im gonna be long winded to explain what I have done and ask what needs to be corrected. Approx. 3 weeks ago had a tub spout drip that turned rather steady. (second floor) With this I replaced the cartridge first., still leaking, then the pressure valve and it stopped. (greased all o-rings) All good!!...Then last night noticed a steady water drip below the shower in my unfinished laundry room while my boy was showering. With a light i saw it dripping from inside the wall behind the handle/cartridge connection. Turned water off took trim kit off and cartridge to inspect the seals., looks good re-grease put back turn water on - no leaks... as soon as I pull lever to turn on shower the leak starts again from behind the cartridge. If I pull shower diverter and put water to shower head it leaks even faster. Did this without the trim on to see if i can see where its coming from., looks to be from where the cartridge meets the pressure valve. So then out of curiosity I turned the main off took the cartridge off and then put the main on, water seems to be coming out of the valve H/C with no problem and there did not seem to be any leaks from the housing or the pressure valve. Then turned main off again put cartridge back and turned main on again and again a steady drip ONLY when the lever is pulled to feed water to the shower.. There is NO leak while the handle is in off position. So questions???..could it be the cartridge went that fast? did i tighten it too much installing something and broke something?... Please help., I am reasonably handy but am the king of leaks. Any suggestions would be appreciated. Thanks ahead of time.

it sounds like something didn't get put back together correctly.
can you identify the valve model and find an exploded vied on-line?

Thanks. I watched about 25 videos all over the place, haven't found anyone to have the leak in the same spot. It's pretty fool proof it's a cartridge that meets the valve with screws to line everything up and o-rings to prevent leaks that's why I'm so frustrated. Just picked up another cartridge going to see if I swap it out if it helps if not it's time to ring a plumber. Any further suggestions are appreciated.

did you get a new "O" ring with the new cartridge? sometimes "O" rings can get stretched so they are more like a "U" than an "O"..

Yeah, I picked up a whole new unit. I'll post baxk..gonna swap.it tonite after work. Thanks again

So, the leak was coming from back of the cartridge couldnt tell if it was the orings or the seal on the pressure balance valve. Bought new cartridge, replaced and still leaking., took out pressure valve re-seated the large o-ring behind the face of it put a wrap of valve packing, greased, re-inserted and so far so good., hope it was okay to add the packing., if it fails, i guess time for a new valve., this one is only 3 weeks old.

time will tell...
it does make you wonder about the engineering behind products..