Will my American GPA be 'transferred' to an Australian university?
While every university is different, it might play a part of the admissions process, but after that, probably not, no. It’s likely that you won’t even receive credit for the units that you’ve done directly; instead, you’d ask for Recognition of Prior Learning (RPL) and they’ll look at the units you’ve done and compare them to the units you’d need to do for your new degree, then give you non-graded passes for the units in your degree that they felt were roughly equivalent in content and teaching level.

Additionally, most Australian universities mark on a seven-point grade scale, ranging from 1 (Low Fail) to 4 (Pass) to 7 (High Distinction), which wouldn’t be directly comparable to the American 4-point system.

Source: I’m an Australian who transferred between two different universities and degrees during his undergraduate, and is currently doing postgraduate study. This is just my personal experience; I’m open to being corrected by someone with experience working in a university’s admissions office.