Voltages go crazy when using 74LVC8T245
My fault! The DIR control pin was not being set to 0V apparently so B port was an Output instead of Input port.

This IC is 5V tolerant that means you can put 5V signals even if you are powering it with 3.3V. Read about this here: http://e2e.ti.com/support/interface/etc_interface/f/391/p/281884/987616.aspx#987616