6/1-30 (Drag Washer)
 
If you have the older parts as shown to the left in the photo and need to replace either the drive plate, drag washer or pinion gear, you will need to get both the newer 117DN drive plate (with drag built in) and the newer pinion gear. The older parts are not compatible with the newer ones. There was also a stage in-between these two where the 6/1-30 washer on metal plate was used with a different version of the 117-30 drive plate that was flatter.