According to this TurboTax FAQ that includes important dates, the military filing deadline for those working abroad is June 17, 2019. So you still have time to file without an extension.
https://ttlc.intuit.com/replies/3302298
It's too late to file for an extension for tax year 2018. That deadline was April 15, 2019.
*** I am NOT a tax expert. I am a seasoned TurboTax user, and volunteer to provide assistance to TT users. Nothing I post is to be considered TAX ADVICE; I bear no legal liability for responses.***