Replacing diverter in Temptrol shower/tub - Model A

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I have removed, with great difficulty, the diverter in my shower/tub Temptrol mixer, Model A. I am replacing the white diverter, with the appropriate diverter for the Model A, which is white. My problem is that I can't seem to get it into position correctly. I can't get the diverter to go all the way in. It sticks out about 1/4" so that the end (and the gold piece) is not flush with the surface that has 2 screws. It is in the correct position to allow the handle to be inserted as intended. I turned the water on and water flows to the tub ok. When I move the diverter handle all the way to the right, water comes out of the shower, but not very forceful and a lot of water comes out of the tub faucet. I understand that a 'trickle' is supposed to come out so that the diverter handle is not used to shut off the valve. But the volume is only slightly less than with shower off. Is the diverter supposed to be flush? Am I doing something wrong? Thanks.