Update... dealer said it was out of warranty. Cf Moto USA said there was nothing they could do about it unless it came thru a dealer. Tried to drill the broken piece but it wouldn't budge. Tried to weld a nut but it was broken off too deep. Tried to drill it completely out an re-thread and the shaft was too hard. Ended up welding a thick washer to the end of the shaft after putting everything back together in the front part of the housing. Welded slow and kept it iced so it wouldn't hurt the seals or bearings. Since it came apart in pieces, putting it back in without removing the axles and differential was a challenge but after removing the 3 differential mounting bolts and moving the differential back as far as possible, the twisting the front of the differential toward the passenger side, I was able to work it back in.
Long story short... it is smoother than it's ever been. It started with a serious jerk every time in low, high or reverse. We c always wondered why ours was so rough and the videos we watched made them look smooth. The excess movement of that shaft, coupled with the jolt from the clutch made it crazy rough.
If you have one that starts rough, check that bolt.