I just took apart my Ascender transmission and did some work on it, because it still wasn't shifting quite as smoothly as I wanted. When I opened it, I found scratches on the square shaft that the shift puck slides on. I knew that the shift puck sometimes tilted on the square shaft when the shift fork pulled the shift puck to one side or the other, but I figured the hardness of the metal and the grease would make sure it didn't bind too much. I was wrong.

So, I washed everything and then went to work with a small diamond-coated file. I smoothed-out the square hole in the middle of the shift puck, paying special attention to the edges where there were mold-lines from the sintering process. Then I got some 400-grit emery paper and laid it on a flat surface, and smoothed the surfaces of the square shaft. Then I polished the square shaft with a 3000-grit sanding sponge, and polished the inside of the square hole in the shift puck with a small strip from that same 3000-grit sanding sponge. Then I washed everything, greased everything, and put it all back together. Now it works perfectly.



Also, I shimmed the shift servo-saver spring to make the servo-saver stiffer:



The shims preload the servo-saver spring so the servo-saver can transmit more force to the shift linkage.