Starter goes "KLUNK"

First thing to do is make certain the engine is not stuck. This could be something jammed up in the flywheel/ converter area, something wrong with the engine or trans. Try to turn the engine with a socket on the dampener bolt.

Next, string a wire somehow and clip it to the big battery terminal. Connect to your multimeter, and ground the other lead to the block. "Jumper" the start relay (making sure it's in park/ neutral by jumpering across the two large bare terminals on the start relay. Hold it engaged long enough to take a reading on your meter. Must read the meter while starter is engaged. You want to see AT LEAST 10v and better higher. If it is below that investigate bad battery cables/ clamps or dead/ bad battery