Crits and CrushesFollow

I've been an expierenced tank for 2 years now almost always taking the MT spot where ever I went, however right when WotLK came out I didn't play for five months and just recently got back to the game and just hit 80 this last week. Today me and a DK tank fellow guildy were arguing about the defense cap and being crushed/crit. I understand that for heroics i's 534 defense and raids 540 for uncrush but what about crit? He was saying that crit basicly doesn't apply anymore and if you are defense capped you wont get crushed or crit. Now is this true or do the old rules of avoidance still apply. I just wanted verification to this for my better understanding. Any information on this would be helpful tank you.

Why are you re-posting a duplicate post from over a week ago (which is still even on the front page) where your IDENTICALLY WORDED QUESTION was already answered?

Original post

Hell, you even mis-spelled the same words ("expierenced", "i's", and "basicly") - looks like a complete copy/paste job.