Diverter valve stem pulling out

Forgive me in advance for calling things by the wrong name

Our tub spout has never diverted 100% of the water to the shower head and has always leaked into the tub a little while the shower was being used. However, now it diverts maybe only 60% of the water. Also, we have to be very careful when we pull it or the stem comes right out. What's the best way to fix this? Do I need to replace the whole spout? There is no set screw on the bottom side of it, so I'm not sure how to remove it if necessary.

Here's a picture of what I have:

http://www.flickr.com/photos/23641540@N05/?saved=1

Thanks in advance!

Andrew

Spouts are not repairable. You need a whole new spout. Look near the wall to see if there is a set screw holding it in place. If not, just unscrew the whole spout.

I usually bust off the outer shell of the spout so I can get a holdback wrench on the pipe inside it... Kinda like crackin open a lobstah!

faucet

That is a Mixet faucet and many of their spouts were slip on with a set screw, but if yours does not have one, then it unscrews from the pipe.