Try
git diff k73ud^..dj374
to make sure to include all changes of k73ud in the resulting diff.
git diff compares two endpoints (instead of a commit range).
Since the OP want to see the changes introduced by k73ud, he/she needs to difference between the first parent commit of k73ud: k73ud^ (or k73ud^1 or k73ud~).
That way, the diff results will include changes since k73ud parent (meaning including changes from k73ud itself), instead of changes introduced since k73ud (up to dj374).
Also you can try:
git diff oldCommit..newCommit
git diff k73ud..dj374
and (1 space, not more):
git diff oldCommit newCommit
git diff k73ud dj374
And if you need to get only files names (e.g. to copy hotfix them manually):
git diff k73ud dj374 --name-only
And you can get changes applied to another branch:
git diff k73ud dj374 > my.patch
git apply my.patch