The large damaged hole is for item "WW"
The small pin hole is for item "AD"
This is what it looked like when all the parts were on it:

Item 21 mounted on your item WW above.
Here's another view:
And here's yet another view:
If you intend to have an operational parking brake you will need to find a new one of these Retainers, PN WO A9330 or A9341, ORD# 7371373, FSN 2520-737-1373, Spicer # 6507X or 18-19-28, Warner Gear # AJ2A7 or J2A7. Where 2 PN's are shown the first is "The retainer with the bearing" and the 2nd is "The retainer only".
All of the above views are in my photo album where you will find several hundred detailed technical photos in their appropriate sub-albums. Try it. You'll find it quite useful for solving problems and answering questions.
My album is easy to find. It is the second album in the "Member's Albums" file.
http://www.willysmjeeps.com/v2/modules. ... _album.php
These photos above were in my sub-album titled "M38 Running Gear"
http://www.willysmjeeps.com/v2/modules. ... _album.php