I talked quite a few dealers today, and read alot of forums. The gearcase is the same as it used to be on the m7, when they went to reverse gearcase they had to use a thinner bearing. When they came across the engine reverse they were still using the single wide bearing, and this is where the problems started. I have found out the bearing off the m7 is the bearing we should all be putting in and THROWING the spacer away that is in between the bearing and gear. The arctic cat part number is 1602-348 and it is a 17 by 40 mm which i believe is the same dimensions as the 5203, but i like ac parts in my ac stuff so i will be gettting the 1602-348. Sorry for the novel boys