I put my hand up on the front of the axle by the yoke while it was turning and it was very rough feeling.....4.30s are known for bearing failures from what i hear.Bearing speed is an issue.U-ju=oints are all good and tight and the gears have the same amount of backlash feel as they did when they where new.I ordered a bearing kit today and my wife is going to get it so i can get it tore down tonite and replace everything.It sounds to me like one of the temken bearings flat spotted and are making noise under load.