Thomas G. Weinandy is here to answer the question for us. Actually, he isn't "here" per se, but over at First Things, with an article based on his book, Does God Suffer?
I have not read the book, but judging from the article it is definately worth my time to do so and this task has been added to my to-do list. As for the article, it is a very fine discussion of the question of whether ornot God is impassible, and precisely what is at stake in answering this question. In addition to my recommendation of this article to all those who are interested in this question, I should like to make two comments. First, it seems to me that Weinandy is too quick to lump T.F. Torrance and Karl Barth in with Jurgen Moltmann on this question. But, we can forgive him since he is only doing a quick overview in this article. Hopefully his book is a little more nuanced here. Second, I have not decided as to how far I can go with Weinandy on the specifically Christological sections of this article. I think we can be sure that this section is greatly extended in the book, and I look forward to examining that at a latter date.
That said, do check out this article.
Thanks to my buddy Shane for bringing this article to my attention.