If that loose ferrule came off the other wiper transmission, you have a problem. I don't know if it is possible to reattach it to the shaft. Maybe a TIG weld would work on those dissimilar metals. One time I accidentally welded two pieces of aluminum together with a stainless steel filler rod. It was not a strong weld, but it did stay together somewhat.
If not, you will need to buy a new wiper transmission or find a good used one.
