Left handed window operator Truth Entry Gard operator for left casement window

Need to replace Truth Entry Gard left-hand window operator

Opens window but does not close without manual assistance worm screw pulls out from the mechanism

Think I need a complete mechanism

The number on upper arm 20810

The number on lower arm 31229

Pics depict the top view and under window attachment in the left-hand photo

The window was made by

in Morgantown Pa. in 1997

Please indicate the product and how to purchase, please

John