Hi, all !
I am doing OK on ELITE, I got MAX resists, even higher now- my char. = 84 ALL res. apart from bleeding res. My DPS is =30 800, I have life steal BUT I still fucking die all the time vs CARRAXUS in that cave.
I am a lv 80 WARDER-- my skills are OK, following the malawi 's guide. WHAT to do ? Please, I need some advise… Maybe MY DMG IS LOW, that thing has too much hp 
Well. DPS doesn’t mean anything if you have very low resist reduction. Carraxus is a crab and maybe has high lightning res if you are lightning damage. 30k dps sounds OK for where you are and so that shouldn’t be the problem.
If all your res are capped all I can suggest is that your armor is low, Carraxus causes your resists to reduce including physical and/or your defences and sustain are not high enough.
That boss is pretty easy to kite around the room he spawns in though so you can just run when potion is needed but on cd.
Also pay attention to lifesteal. Maybe you trying to facetank him without lifesteal that causes your HP going down w/o any chance to restore. Use components and devotions to increase lifesteal and that big piece of crab will die in torment:)
No , I have more lifesteal than I need in fact / from 2x sources / . I found I had to kill his summons first , I was just facetanking him and hitting only him without moving. Micro was the key to victory.