need to replace the internal worm gear inside Truth casement operator crank handle

Thanks for reaching out! The worm gear cannot be replaced in the operator once it becomes stripped, unfortunately. It is not sold separately, so you'll need to replace the entire operator.

This window operator looks like it could be a match for the 39-470 Front Mount Scissor Arm Operator. To determine if this is the correct replacement, carefully review and compare the dimensions below.

Thanks confirming. Your window operator has measurements are similar to the 39-473 Rear Mount Scissor Arm Operator. Although, since yours is front mounted you'll also 33-205 SS #10-24 Thread Nut to complete the installation.

Dimensions for 39-473