Hopefully someone can help me here. I am running b2920 with mower deck. The mower will go up with no issues when trying to put it down the lever feel hung up an wont let the deck drop. When i shut the tractor down it still wont drop unless i pull up on the lever like 10 to 15 times since it goes down in slow increments. I looked an made sure that knob was in the right position below the seat that was ok. So what is my issue?