Clunking problem in 2001 Impala

This Impala we got makes a clunk sound when you put it in drive, park and reverse. It also makes the clunk sound when you accel or brake hard and when you go through hard corners. Started as a sound but now you can feel in steering wheel. Need help, any response is appreciated.

check the lower control arm bushings and motor mounts first.

Sounds like a motor/trans mount(s).

Go to a dealer and ask for copies of these Service Bulletins: 99-04-20-002D issued June 2006. You won't like this one, it basically says for dealers to not try to fix your problem.
02-08-61-001B issued 11-06. This one talks about various parts of the engine cradle rubbing on stuff.
01-02-32-001H issued 2-07. This one is about the intermediate steering shaft needing lube.
There is a bulletin out about the engine cradle itself sliding back and forth under braking and acceleration titled "Clunk/Pop from..." I can't find my copy and don't remember the rest of the title. The fix it proposed was to install some shims in the back rubber bushings of the engine cradle. I don't remember if it applied to the 2001 or not. It worked on my 2000 3.8, though.
Hope this helps!

Could also be brake pad material separated from backing plate(s). I have also read that there was a problem on 2001 engine cradle welds and there was a recall for inspection at dealers...don't recall where I had read this, it was 2 years ago.
Either way, please post in this thread when you discover fix.