I have a L3130 DT with a 730 loader. This is my fisrt tractor and I am still learning more about every time I use it. It now has 35 hours on it. I noticed that when I first start it up I can hear a buzz noise from the hydrolics in the rear of the tractor. It only last a few seconds. I don't know if this is a new noise or maybe I did not notice it before. Any thoughts ?