^^ werd.
are you making your own drum tracks or using loops? if your making all your own drums and they sound too clean for ya, ya just gotta start laying some harsh effects on em if ya want a gritty sound. like was said, use heavy eqs, heavy compression. use some 'overdrive' or 'distortion' fx, or whatever you have that adds dirt to sound. try ohmforces predatohm. that thing will dirty up anything. add some subtle hematohm over top and you got straight grimey! but make sure you got the basics of eq and compression down first.
and it always helps to start with the best possible source material you can, even if youre goal is to degrade it in the end.....
peace.