http://board.marlincrawler.com/index.php?topic=11245.0Very valuable thread. I'm surprised it didn't come up in your search results. It is a sticky after all.
I'll repost your answer here too.
Gear Drive T/Case: 1.5 - 1.7 Quarts
Crawl Box: ~0.8 Quarts
Crawl Box + Gear T/Case: 2.3-2.5 Quarts