The military MyPay site is down and I can't retrieve my W-2 so I don't know the gross income or withholding amounts. In military out of country. Need to file 2 mo. extens

Currently in U.S. Marines based in Okinawa as I have been throughout 2016 to the present.  Don't know my gross income and withholding amounts as the military MyPay system is down and I can't retrieve my W-2.  Would like to file two month extension.  Do I need to provide those amounts on the form?