Hey Guys, I have a 52" z-rider about 4yr old with 550 hrs on it. I purchased the unit 2nd and suspect it had little maintance. The problem is the hydrosteer is very noisy, sort of a hi pitch growning when in forward/reverse. Both of them make the same level of noise. They have been that way ever since I have owned the mower about 150 hrs ago and not got any worst. The noise is quite annoying and can be herd over the engine and deck. Any idea's, replaced fluids, bearings, rebuild replace pumps?????? Cheers Reece.