What type of oil did you add...
How many hours are on the tractor, how many hours are on the oil?
How many hours are on the filter?
also a quart is about 15 percent of the total capacity, so you could have air in it.
you may have better luck getting any air out of the system if you jack the drive wheels up and power them forward & reverse until everything is operating smoothly. :smile:KennyV