i have a bx 2360 2012 model ,my problem is when i want to adjust my deck height the knob is almost impossible to turn or will not turn at all ,i know I'm doing it the correct way because when the mower was new it was no problem at all ,very simple twist an i was good to go but now i don't even want to attempt to adjust out of fear that i will get it stuck at a height that i can't use ,any help or suggestions would be appreciated ,thanks