I have had my GRS 1 for over six years without any problems until here recently. It started popping out of 4wd. There was no rhime or reason it would pop out whenever it wanted to. This weekend I pulled it out to look it over. This is what I found. The shifting rods have three detent balls for the normal shifting pattern. For 2wheel low operation they remove the center ball. On my t-case they removed the ball just the wrong one. They left the center ball and removed the one that was for the 4wd engagement. I guess the center ball would just hold it and over the years I guess it weaken. I guess I was lucky over the past years with it.