We broke a tooth off the drive cou[pleing while processing food.

When the part came it had complete repair instructions with it. I followed the instructions and it was very easy. I had to pry the old coupleing off the threaded shaft. You wouldn't think that would work but the coupleing was made of soft metal so when you pry it off the hard metal shaft it didn't mess up the threads. Then you just screw the new part on counterclockwise and the first time you use the blender it tightens itself. Very easy!!