Can you help me figure out what to replace

Hi there!

If your worm gear is stripped, you'll need an all new operator. For the one that's in your 3rd picture, start by taking a look at our 39-031 & 39-032 or the 39-155 & 39-156 operators. Review our dimensions and compare them to yours to see if one of these matches your original assembly. For a handle that's compatible with these operators, see our 39-205 and 39-114L depending on the style you prefer.

The one in your last picture is different from the other operator you show, however. If you need that one too, we'll need to see a picture of your operator with the window open so that the arms that move the sash are fully visible. 

And yes! You can see our return policy here.