eljuan - Those nav links for the six pages are called "Sitelinks". What you're saying is that you don't get Sitelinks for your brandname searched without the .com. I've just checked this on some sites that I thought were really dominant for a two word keyphrase run together, and though most did display Sitelinks without the .com extension, some did not.
Google has gone through all sorts of display threshold tests with Sitelinks, and I suspect that they will continue to do so. Though the Sitelink algorithm has never precisely been defined, I initially associated it with dominance of a site for a particular query. If a site was very dominant for the query, and its navigation was reasonably well segmented, it would be awarded Sitelinks.
This, over time, has been scaled back... to the point now, I'd say, where the query has to be extremely likely to be navigational in intent for Sitelinks to be displayed. In some cases, the query without the .com or other tld extension is perhaps not unambiguous enough.
You had also asked...
I'm also wondering if it might be an issue with the Nav bar being drop down.
This really didn't make sense until you clarified your question. It does now, and you may have an inkling of some of what I'm about to say.
The Sitelinks themselves are shown for what are probably the most popular categories on the site. Drop down navigation, also known as mega-menus, can present the user with so many choices that Google may not have a clear idea of what your most popular categories are.
Extremely well-known, well-linked 800 lb gorilla sites can get away with mega menus. In general, though, I think that mega-menus or drop downs tend to fuzz things up quite a bit. It can take a lot of PageRank/inbound link juice to allow any of your homepage links to register on Google with sufficient clarity for Google to understand what's important on the site.
Thus, Google might need the .com just to provide enough disambiguation to narrow the query down precisely to your site... and then to make further choices from there.