aweful cracking sound ,need help

My money's on the k-frame/LCA pin tube weld being busted loose. Some good suggestions so far. Do a close inspection, looking at everything from bushings to frame structure first.

AJ's right on for checking the suspension, put it up on stands, pull the wheel, back out the torsion bar adjuster and cycle the suspension. You'll probably need to drop the adjuster bolt all the way out so you can pull the adjuster plate to give you full motion. If you can't hear it right away using a jack to cycle the suspension pull the shock so you can cycle the suspension by hand. You can move stuff faster than you'll be able to with the jack, and you might be able to feel the play from whatever is making then noise.

Other than that and a close inspection you'll really have to start taking it apart to find the culprit.