[highlandlake]

Hello Paul, welcome to AF.

I have a 2004 and just went outside to see what mine looks like.
Although I'm not sure exactly what might be missing on yours, the arm on mine is held on with a clip. That clip appears to nest inside the female socket on the arm. I'm talking about the socket that is on the arm closest to the attachment point on the rear door, and this socket fits over the splined motor shaft. Hard to describe I know.....but perhaps you can go to any new or used dealership and take a close look at an Escape on their lot.
You'll see the clip I'm describing.
I haven't had to remove the arm on my '04 but on other cars I've owned I had to use a flat blade screwdriver to release the spring tab to get the arm off. This one looks very similar in design.
So, I'd recommend going to a used parts place, or as a last resort the dealer to get a new full arm assembly.
Let us know how you made out. Good luck.
Tom