TV REVIEWS : PREVIEWING THE NEW FALL SEASON

“Sledge Hammer!” premieres at 8:30 tonight on ABC (Channels 7, 3, 10 and 42) with an episode that lends itself to great on-air promos. You’ve probably seen some, with David Rasche as the quick-draw Sledge, a Rambo and Dirty Harry sendup, having conversations with his .44 magnum.

Very funny. In fact, the first 10 minutes of this special premiere, written by producer/creator Alan Spencer, are very funny, topped by Sledge’s blowing up of a building to get a sniper.

As the series will normally be seen at 9 p.m. Fridays opposite (gulp) “Dallas” and “Miami Vice,” he probably wishes Larry Hagman and Don Johnson were inside.

Immediately thereafter, though, the story flattens out.

“Sledge Hammer” is one of those broad, one-joke, gimmick comedies--”Police Squad” was funnier--that seldom succeed on TV because they are hard to sustain. A second challenge for “Sledge Hammer” is that it’s spoofing a genre that itself is almost a self-parody, hence the comedy tends to seem almost redundant.

In any event, overkill is something Sledge would understand.