or is it a partition on the C drive?

If the latter, did you format the entire drive?
If the former, then when you installed iTunes again, it would have created an iTunes library which, by default, would have been on the C drive.
At that point, given that the D drive was still intact, there would have been no need to move anything. Just point iTunes to the existing D drive iTunes folder and you would be back in business.
There is no Sync involved, it is just a matter of pointing iTunes to the correct Database.

On the subject of exporting. You can export a copy of the playlists, but not the actual media, and you must choose XML format as stated in the help file.
Did you do that or did you choose another format?