Reefwaters-
What setting is the pin spacer on and are all three pins properly installed into the heat sink? It is VERY common for customers to have problems like you are describing because the pins have been bent at one point during installation. Usually a new pin spacer is needed in these cases. We will be making this part out of harder material in the future to avoid this problem. However, if the part is properly installed then it will function fine.
If the pin spacer is properly installed, what version of the new wet gasket do you have? Is it a hard plastic part with foam stuck to it that snaps into the back of the wet frame? Are you using the thin, floppy, black gasket on the dry side of the tank?
If all of this checks out, just up the pin spacer setting to 1/2" and it should be a lot better off.
Finally, you may just be in need of the ceramic drive shaft as your plastic one has worn out. Fortunately, the ceramic ones really don't ever wear out.
-Tim