Truth casement window hardware

I have a right hand casement window that isn't operating properly. The gear in the crank housing doesn't stay in place and slips out of position. Also there is a nylon guide for the locking mechanism that is missing that I need to replace. (I've included a pic of the left hand nylon guide) The only identifying marks I see are "Truth" stamped on one of the arms and the number 41011 stamped on the under side. Any help would be greatly appreciated.
Mark Rix

The missing nylon guide is also on the right side.

Thanks for your assistance, this looks like it will work.?

Could you compare my operator cover, doesn't appear to match the ones listed. The closest match looks like the 39-451 but my operator is only 5 1/8" long. Also can't see the end view dimensions on the 39-451. Mine is approximately 1 1/4" tall and 1 3/8" deep. See pics below. Again thanks for any assistance you can give.

All set, you've been very helpful

This was helpful for my project, especially the part about the nonremovable cover and the customer's picture of the removed operator. Thanks