The GMC dealer did not have a bulletin from the manufacturer so it was not under warranty. I told them what the problem was so they removed the driveshaft and greased the transmission spline as I had asked.

The problem is ongoing and I live with it by having e shaft removed and greased with every oil change.

I have talked with others with the same problem so it is not just me.

I have also been told that it has the wrong driveshaft but I have no idea if that is true. I don't know how to tell if it is.