you can't file a joint return without her SSN and consent filing a joint return without spousal consent is a violation of the tax laws. you can file as married filing separate and without her SSN but would have to mail in your return. you would attach a statement that you are married but wasn't able to get her SSN. list her name and last known address.
if you filed joint last year a transcript of last year's return will do no good because it only shows the last 4 digits.