American Standard Diverter problems

I may be cross threading but promise not to do it again. Wasn't sure if I picked the right forum initially.

I replaced the stems on a 1972 vintage American Standard Colony set. I fished 'most' of the peaces out of the old ones, replacing cold, hot and divertor colony long stems (link below for picture of diverter) http://www.suttonplumbing.com/pc-470...rter-long.aspx

I have good pressure but from the gitgo I was bypassing too much water to the tub spout when fully diverted to the shower. I finally called a friend, a full time plumber to come look at it.

He took it out, did what he wanted and put it back. Still bypassing water. He said give it a couple weeks to fully seat. (Fine freind, huh?)
Well, a couple months later my wife is about to kill me if I don't fix it.

I pulled it out and it tried to stick like the old one when I pull it. When I got it out, the backing screw stayed in. Fortunately this one didn't fall down the valve body and I fished it out.

Now, the questions. Do I lock-tight that sucker? Tighten it down tighter against that nylon bushing? What is grabbing it and working it out as the diverter is rotated?
Why can't I get more water to divert to the shower? No probs fully diverted to the tub spout. I could understand if I was getting water up to the shower when trying to use the tub spout. Like a partial obstruction from a dropped screw or stem peaces? I just don't visualize an obstruction up to the shower.

Any help is of course very appreciated.

diverter

We have absolutely no idea what you installed, or whether it was the proper unit, or how you installed it. But regardless, it either works immediately or it doesn't. It does not "take a couple of weeks to seat itself".

I didn't realize I was that vague, I'll give it one more shot. I did notice the link to the picture of the diverter valve didn't work today.

Here is another link, http://www.plumbingparts.org/parts/982878.html.
American Standard 982878 New Style Diverter (lgth., 5 3/64")

Another site ( http://www.************.com/invt/u820897 ) lists it as
Diverter Stem, For American Standard 3 Valve Tub/Shower Faucets, This Stem Is The Long Pattern Version F10-1uh & Fits ``Colony`` Models C101-2, C102-2, C103-2 & C104-2. Model Number: ST5001

My plumbing friend did verify it was the correct replacement model. As to how he installed it. I guess I was hoping to hear how you incorrectly install one. He lubricaed the threads, and after hand threading it, tightened it down

wow. great site for advice.