Here is an interesting tidbit for anyone tackling this project. Look at this particular nut in the diagram. Number 15. This nut needs to be whacked with a hammer once it is torqued to help secure it to the shaft. If this nut is removed it Has to be replaced with a new one. There are a total of three such nuts for this project. If you replace the drop gears you will have to replace these three nuts. It would be irresponsible to reuse them. They are distorted once you take them off the shaft. Note that the other two nuts have the same part number but they are not 20mm. I believe they are 27 mm but I’m not sure. The diagram available online has the right nuts.
The problem i encountered is this. There are two separate part numbers for these nuts as shown in the diagram. The diagram represents the nuts in picture I also posted . I originally ordered the 22 mm nut but was a little bummed last night went I went to install the nut and it was the wrong size. I knew the actual size because I had to tap to check it. The size I needed was a 20 mm but when I ordered a nut from a US-based diagram I got a 22 mm part number. I was sent a 22 mm nut based on the diagram I reviewed from a us based deslership. Why are there two different nut sizes? I cannot say. In fact most parts diagrams only reference to 22 mm nut. I goigled this posted diagram showing 2 part numbers by chance. The diagram is in another language and it showed two different nuts. Using the part number on the foreign diagram I was able to order the proper 20 mm nut and it should be here within the next couple of weeks. The sad thing is I waited three weeks to receive the 22 mm Nut from Germany. That nut was $100