Have had my TimeCutter 54 for 6 years. Live on a farm with about 3 acres of grass to mow. Know the yard like the back of my hand. Do it the same way every time. Mow most areas at 2.5" setting, other area at 3" setting due to thickness and coarseness of the grass species. About two weeks ago I noticed 'lines', or 'ridges' halfway through my swath. And then it started scalping where it's NEVER done before. I'm talking about very very slight grade rise so slight you can hardly feel it. As if the deck isn't floating anymore. And it's scalping like you're grading a road! I've checked tire pressure, put it on concrete to see if the scalping wheels were hitting square (slightly off on the right side, but could have been like that all along?) I admit, I do not clean my deck very often, but in 6 years I never have been consistant. Now this problem. Any hints at what I can look for? Start by thoroughly cleaning the deck? It's driving me nuts because it's never done this before. AND I can't mow any lower or it scalps constantly, another new thing...instead of the seas rising, I think my land is.....help!