Hello everbody; i am new to this site and recently purchased a 1978 Case 220 with tiller, front blade and mower deck. My son was tilling my neighbors garden and got a leak in one of the hyd. hoses. he drove it home and we put on new hose and refilled with Rotella 15w40 oil. When i go down a hill now it seem to make a growling noise and it seems to coast a little bit. it almost seem like its low on oil, but its not. The tiller still works great so i don't think its the pump. Does anyone have any suggestions? I am wondering if the wheel motor is going out. Thanks for any help.