THERE'S a violent new movie in town jam-packed with all the things teenagers are supposed to love: rock music, gangs, fast cars, sexy high schoolers (who cares that they look 26?), and a cast of characters who've been populating teen films from "Rebel Without a Cause" to "Grease II."

Unfortunately for the makers of "Tuff Turf," the plot's as hokey as they come; the dialogue is dreadful ("Life isn't a problem to be solved, it's a mystery to be lived!"); and kids in 1985 are just too sophisticated for such juvenile tripe. Right kids? Right?

The premise of "Tuff Turf" is interesting. Alienated teenager Morgan Hiller (James Spader) transfers from an eastern prep school to the wired world of a Los Angeles public high school. Director Fritz Kiersch artfully depicts preppy Morgan mingling with the Spandex-clad, switch-blade- toting toughs who own the halls of his new school. But things take a turn for the worse as soon as the characters actually start speaking to one another.

No sooner does Morgan enroll in school than he incurs the wrath of some bad boys by pursuing their leader's girlfriend (Kim Richards). And in no time, eastern preppy must do battle with western street gang.

"Tuff Turf" quickly degenerates into an unsavory display of bloody rats, locker room beatings and Morgan's terrible love crooning: "I hear your eyes, we lick our wounds." The climactic battle scene features gunplay, face-busting, two raging dogs (nothing like Dobermans to scare off punks, ya know), high platform falls, and lots and lots of blood. Go team.

An excellent sound track, led by new- waver Jim Carroll, almost makes "Tuff Turf" worth a look. Many of the performances, notably Robert Downey as Morgan's best friend, occasionally ring true. Bt nothing short of James Dean rising from the dead can save "Tuff Turf."

TUFF TURF (R) -- At area theaters.