The crank is not smooth. It jams up and there is a lot of play. Window from 2004. Insure of manufacturer. Looking for both left and right
One arm has a stamp of 31858 and 31876
Thanks for reaching out! It sounds like your casement operator gears may be stripped, so its a good thing you are looking to replace the entire mechanism.
Your casement operator looks like it could be either our 39-253RB or our 39-439B; the opposite handed version of each of these operators are the 39-253LB and 39-438B, respectively.
To confirm which of these is the correct replacement, you'll need review the video below. Take note of the differences between each operator and compare them to your existing hardware to confirm which of these you need.
