struts and shocks could be bad go to a mechanic and have them checked
Probably a worn out suspension bushing.
Bumps in the road.
Most likely a bad motor mount, bad U-Joint / CV Joint - try to pay attention to make sure the transmission is 'shifting' when it happens; that will help you find the problem.
There are several things that can cause a clanging noise on your 2004 Toyota. A loose exhaust pipe is the most common cause.
That would be your transmission. It may be slipping, or you may be lossing a gear. Have it checked.
harmonic balancer is coming aprt poossibly. the rubber that holds the inside metal hub and the outside metal ring rips and there is a metal hook and latch that hits each other to keep them from seperating. This makes a metalic clanging noise, and is close enough to the a/c compressor it sounds like that is making the noise. originally a recall item and is replaced with same exact part and will do it again in a couple of years.
wheel bearing?
The rubber bushing for the suspension spring has fallen off from age. The suspension spring now "slaps" itself, metal to metal, causing the noise.
Loud, confused, harsh noise; a loud, continuous, rattling or clanging sound; clamor; roar., To strike with confused or clanging sound; to stun with loud and continued noise; to harass with clamor; as, to din the ears with cries., To utter with a din; to repeat noisily; to ding., To sound with a din; a ding., of Do
remove the belt if it still clanks major motor problems
Loud, confused, harsh noise; a loud, continuous, rattling or clanging sound; clamor; roar., To strike with confused or clanging sound; to stun with loud and continued noise; to harass with clamor; as, to din the ears with cries., To utter with a din; to repeat noisily; to ding., To sound with a din; a ding., of Do
Possibly a broken shock or bad stabilizer bushings