Can I damage my transmission with no vacuum?

My tranny shifts super hard. After replacing my IP shutoff, and verifying that the pump and booster are solid, I still have vacuum issues. There are three lines heading into the pass compartment that will not hold vacuum. I have plugged them, but still shift unreasonably hard. Until I get around to digging out the heater, doors, ect., am I in danger of hurting the tranny?