Have a Dixon SPDZTR 48 year 2011 or 2012. Lately having issues with the steering. No power on grades especially when having to turn. Makes a "loud humming" noise. Seems ok when I start mowing and gets worse. Owners manual shows no help other than air in line may need purging. Can find no tranny oil tank or filter. Belt seems ok, albit it hard to reach, and seems tight. After mowing the pumps seem overly hot in my opinion, but fans seem ok and belt is running them. Hard to find service in my area so trying to get answers on forum first.