Best wishes to Rachel Marszalek and Jody Stowell as they go off into retreat ahead of their ordinations as deacons. That's despite them being evangelicals! Both have been victims of my drawing, Rachel more than many. Rachel writes good essays and has engaged with me at that level, and yet I think a lot of this evangelical sourced postmodern theology (it starts with Karl Barth and journeys through Hans Frei and the institutional George Lindbeck) is much of the Emperor's New Clothes. Another variant is the Radical Orthodoxy that is a kind of bubble of Anglo-Catholic postmodernism. Liberal postmodernism is the one that allows itself to spread out somewhat - Don Cupitt is the British version but the main man is arguably Mark C. Taylor in the United States. Of course there is hardly a boundary between liberal postmodernism and liberal modernism, as with say John Hick, though the latter types retain a form of theism. It makes sense - postmodernism and high modernism go together in the social sciences.
This is how I understand how postmodernisms in different camps come together. In Barth's scheme, the God of revelation is so high and dry you can't see it. No one can approach it - that is corrupt religion. So it has no objective existence, no actuality in history, culture - only in encounter under revelation. So Hans Frei says with no objectivity nor subjectivity it is like the postmodern and is received in the biblical narrative - which is history-like, or biography-like.
So there is a sleight of hand, there. In Radical Orthodoxy postmodernism allows for difference and thus a reassertion of the Platonic, the true and good - but within its bubble. It then gets to be like a bit of a thug (it can when the Church is perfect peace) and says it has the right to truth and something like Sociology is a form of secular theology. Rowan Williams expresses a kind of Radical Orthodoxy by always going on about 'the story' as authentic, except he gets into the detail and you start to think it is historical detail when it could just be fictitious. His Catholicism is highly institutional, as the people opposing the Anglican Communion Covenant have discovered. The Church is the ethic, so there is nothing that the Church need absorb - human rights is an inadequate starting point because they are secular and outside the bubble (though John Milbank is pro-gay inclusion!).
The liberal postmodernism is where each has their own language and nothing is dominant over the other. This is the problem of translating between cultures, discovered in a Social Anthropology that does not want to have Western intellectual terms as superior. You end up with a highly fluid, symbolic religion, Baudrillardian in that the symbols build up and break down. It is the anti-matter with the matter, and never only one of them: so a Eucharist is both real presence and unreal absence and never one. In terms of liberalism, the highly subjective breaks down into the postmodern, especially when the highly subjective tries to live with collective forms, such as shared worship. The Martineau route to postmodernism is the mirror image of the Barthian route; indeed the particular and the general are the opposite. For Martineau the Bible is something that is but an example of something all the greater; for Barth the Bible is the greater and activity identified as religion is the subsumed within it.
For myself, I am probably a high modernist. Sociology isn't just secular theology because it does research and produces, whether valid or regular, answers you don't want. It is not like a novel where you can make it all up. Nor is science. Yes there are ignored questions and big theories to change, and issues of language, but your experiments soon say yes or no in a real sense. The big humanist narratives are not narratives like theology: they actually reflect technological achievement. Theology, though, is open to the postmodern, because it is creative, is fictitious, is artistic. It is a form of reflection, and a means to engage with ethics.
I'm a soft postmodernist in religion in that I don't believe in the existence of God in any directive sense, but it is a useful 'summary' term about our hopes and fears. But I am not a postmodernist regarding science or anything else - I must be a critical realist. Each subject has a different language game, but that includes degrees of objectivity. Religion has realities of exchange and gift, of the communal and binding, but these are not structural: the poststructural and postmodern can run riot in varieties of interpretations.