Squeaks in rear suspension 2002 ETC

I just bought a 2002 Eldorado ETC from a dealer in Buffalo.  100 miles down the road the rear started squeaking and it is very annoying.  I tried spraying all the bushings with no great results.  Has anyone else experienced this and what should I be looking for?
 
Thanks.

Try these posts and see if it helps you out.
 
http://www.cadillacforum.com/m_10869/mpage_1/key_/tm.htm#11206

As it turned out is was the knuckle bushings on both sides plus the right hub assy.  This seems to be a fairly common problem for this year and model.  I hope they have re-engineered the part to last a little longer.  It sure was a pricy repair.