Or bad, new in the box.Lubricate the hardened sliding pin with a couple drops of transmission fluid (its under the small cover on the arm). If this cures the problem, even for a while, you need to clean and lube it properly. If it does not change things, the box is bad.
I have found that the arm cover can be forced down too far, causing it to scrape on the lower housing, This is quite alarming. A bit of grease and prying up slightly cured it for me.
Peter
