Driveshaft Circlip

This circlip fits into one of the three grooves in the driveshaft. The position of it controls how much clearance you get between the flexible coupler and the driveshaft. With the coupler pushed all the way forward, there should be 1-5 mm of clearance between it and the driveshaft's flange. (Tightest spot is straight down.)

If you have no clearance, move this clip rearward one notch. If you have more than 5 mm of clearance at the tightest spot, move the clip forward. Most of the time, the center groove is the correct location.