David,
You really got me. I don't know what you have pictured, but it is not the modulator.
I am enclosing a link which will show you everything you ever wanted to know about rebuilding a 722.3/4 tranny. There will be a picture of the modulator somewhere. I am having a great difficulty with my DSL line and it took me 10 minutes to get the link, so I haven't reviewed it for the actual page. You will find very nice pictures of every part of the trans.
http://www.transonline.com/electroPublisher/website/index.cfm?pageID=2877#