I have been getting geared im above 5.5k gs but i am having hit issues do i need to gem hit or what do high lvl dk tanks do for hit?
Hard to say without an armory link. What do you mean by "hit issues"? Are you missing taunts? Is your threat low?
In general, I wouldn't worry about hit unless you are repeatedly missing necessary taunts. Then you can either glyph Dark Command or switch a piece of gear out. If you look at the armory pages of many MTs, you'll see their hit in the 120-180 range which is fine.
Also remember that if you're dual-wield Frost, you actually need less hit because of Nerves of Cold Steel.