Kickdown not attached 904 won't shift gears

Hi forum,
I have a 1965 Barracuda and it has a 904 transmission with a dodge 318. It stopped shifting gears about 3 months ago. I thought I blew the transmission. A little while before it totally stopped shifting it was slipping, clunking, etc. yesterday I started looking at it and I noticed the kickdown is not even attached. I'm wondering if that's what the problem is. I'm by no means a mechanic and don't know how to assess this. What do you guys think?

I appreciate any help.

Thanks, Gary