I removed the mowing deck, and a video I watched, told me to raise the rear lift arms to get them out of the way to slide the deck out. Now I can’t get the lift arms to lower. I’ve tried to adjust the cutting length so it won’t be stuck in the up position. I can’t raise the deck on a jack up to the lift arm because they are too high and the deck is hitting something underneath the mower. I’m able to start the mower to try to lower the lift arm but nothing seems to work. Is there a safety mechanism in place that I need to bypass??