Have you taken it in for service? There are a lot of moving parts in the top of the machine that have to be moved. Your take up lever, the needle bar, use oil. If the machine is groaning it means it is struggling to make something move. Have her assist it by gently turning the hand wheel toward her as she is depressing the foot controller until the machine gets over the" hump". If this aleviates the groaning, the machine really should be taken in for a good oiling.