Since I had to read the 33 pages to root my Samsung Tab Pro 8.4 without tripping Knox, here's what I did to root it:
1.- Checked my current firmware: T320UEU1AOC1 with Kernel Version 3.4.0-4441590.
2.- Downloaded Odin, the Samsung USB Drivers.
3.- Powered off tablet, then pressed Home + Volume Down + Power, then Volume Up, and plugged in the USB cable after that.
4.- Loaded Odin, clicked on AP, loaded the TR Rootable Kernel from first post.
5.- Everything went smoothly, checked the tablet: same firmware and same Kernel version 3.4.0 but way older (from April 2014).
6.- Went to towelroot.com, downloaded APK, executed it, everything ok, rebooted tablet and it's rooted. Installed SuperSU, disabled Knox (and I have no issues whatsoever).
7.- Repeated steps 3 and 4 but using stormygal's AOC1 Kernel pack found in this post: http://forum.xda-developers.com/show...&postcount=302
8.- Rebooted, still rooted with current firmware and current kernel version.
Thanks to everyone who posted in this thread. I read every post and I'm pretty sure every single one was useful.