Trans, by Rogers Brubaker, is a great book for those wanting to think about parallels between being transgender and being transracial. Brubaker thinks being transracial is more of a thing than you might think (he has some fascinating examples that go beyond the Rachel Dolezal case), and he thinks it's illuminating to think about the two phenomena in parallel. I recommend the book.
Here's one area of difference that he highlights (see pp. 135-142): gender is an individual matter, on any account. We don't have our gender because of anything about our ancestors. Naturalists think we have our gender because of biological properties of our bodies. One trans-friendly view that's starting to challenge naturalism is the view that we have our gender based on our sense of our own gender identity. It's not a huge leap from the naturalistic view to the psychological view, since the sense of our own gender identity is another individual property. When it comes to race, though, ancestry—a question of history— is thought to be important. For example, to be black, arguably, one must have black ancestors. It would be a huge leap to replace the ancestry/history account of being black with a psychological view, since history is non-individualistic, but psychology is individualistic. So the idea that someone could be "trans black"—black based on a sense of being black, and despite having no black ancestors—doesn't go down easily.
On this view, we're likely to be more open to trans-X when we already think about X individualistically, and merely have to shift to a different individualistic basis for X. But we're likely to reject trans-X when we think about X non-individualistically. I think this is confirmed when we think about various properties that depend on a person's life history, "outside the skin." Being a veteran is having fought in a war. If you didn't you're not a veteran, no matter how much you identify as one. Being a Penn State Alumnus is having graduated from Penn State. You're not one, no matter how much of a Penn State fan you are. Being a New Yorker is having lived for a significant period of time in New York. You don't get to be one by just acting like a New Yorker. There's something to this idea that properties with a basis in non-individualistic facts are ones we're particularly reluctant to think about in a "trans" fashion.
Anyhow. Good book, with lots of food for thought!