I recently replaced my toilet on the second floor of my house due to the wax ring leaking. I also had to repair the flange due to the flange being rotted and it was too low for the wax ring to make contact. After replacing the toilet, which is not a power flush model, whenever I flush the toilet, both the sink and bathtub drains make a gurgling noise while the water is exiting the toilet. This noise never happened with the old toilet. Is this a vent issue or something else? Please HELP!