Ok Thanks for the info. During the Fall/Winter months I will take them out and measure them. I think when I take the axle out I will take differential cover off so I can do a good cleaning and refill with some new fresh gear oil.
Maybe that could be a good routine, once every couple of years new differential fluid and new u joints regardless if its needed or not. Or maybe get a plug added to the bottom of the housing or something to make the fluid changing easier. The differential I have only has one plug. . .the fill plug