I just started my rototilling season today ,I worked most of the day just fine but on the last job I went to turn using the wheel brake it really started to growl. I straighten the tractor and tried the other brake and the same thing happened. I had about 5 min to finish the job so I kept going but then I started to feel a vibration in the pto so I quit everything. I used a magnet in the oil to see if there were any fillings in it but could not find any. This tractor has 750 hrs on it regular oil change,trans oil etc as per operator manual so I do not know what happened. Looking for some input, anyone who has a service manual for advise.