Sounds like you've got the wrong gearbox oil grade. If you supplied the oil, check the grade. It should be 75w-90. If the garage supplied the oil, ask what was put in. Wrong oil can not only make shifts slower and harder but also damage the internals.
Regarding the tapping, that's the carbon canister. You can either leave it in place tapping away or remove it completely and block the pipe that goes to the throttle body, leaving the one from the fuel tank open to vent.