I have a JD LX277 that just recently the mower deck will not raise. I noticed that the mower deck adjustment knob will not turn either. I removed the deck and the knob seems to move freely but with some resistance. Also, as I attempt to raise the deck, the handle moves just fine, but the deck will not come up nor do the draft arms. The lift assist spring is fine but I can not tell what is causing it not to come up. I looked on line and found one posting regarding the "Rock arm" which, I think actually raises the deck but it is in a very tough area to get to. Are there any other ideas?