I've never done it with my Previa, but i just finished reinstalling the axles on my 97 4runner about 10 minutes ago. I assume its pretty similar, so...
I'm starting to get noise from my rear axle after 380,000 miles. What an incredible van. The sound doesn't increase going around corners, so suspect...
For the leak on the rear axle, do you mean the rear axles from the differential to the rear wheels? If so the issue with that is not so much the leak...
I finally got it heating, but crap. I forgot all about the engine drain plug, duhhh. That's probably why I'll have to do a 4th flush, duhhhh. Duhhh. ...