Welcome no there is not a retainer. just unbolt the arm at the connection and spray some wd40 on the gear it will loosen up then pull off.
Sorry there is a plastic cap over the nut. Once you get the cover off just unbolt the nut and loosen it up. I am sorry I should have explained it a little bit better for you. Also on some the end of the arm where it pivots there also can be a plastic cover that seperatesto get to the bolt.
Oops! I seem to have a different application. The arms are off now but FYI there is no nut. There is a locking tab piece that has to be slid out (about 1/8") and then pry the whole arm (metal) off. Now that I have the wipers and plastic shroud off I can look for the famous Pontiac leaks.
I've isolated the leak to the firewall. it drips through and dribbles onto the floor, under the drivers seat and ends up puddling in the rear passenger floor well. The original padding was soaked everywhere. I assume it wicked through the padding and just got everywhere, since there are no leaks , other than the firewall. It looks like the wiper motor box could be the culprit, since that seems to be the general area where the leak comes through. My plan is to use an elastomeric caulk around the motor/sheetmetal and see if that does the trick. I live in Oregon so have lots of days to test for leaks. Anything I might be missing? Thanks,