squeaking sounds when going down humps

guys.. problem.. a while ago napansin ko na may squeaking sounds (parang rubber ducky na tunog) na nagmamanifest every time na dumadaan ako ng humps.. kanina lang nangyari pero nung umaga naman, ok naman. :twak2:
ito yung infos:
1. I just reinjected my ball joints last february 2013 sa M7 aurora
2. stock springs
3. tuwing dumadaan ako sa flyover (the one coming from edsa papunta sa rockwell - boni) at medyo mabilis ang dating sa kurbahan (60 - 70kph) , parang lumulutang/nagshishift to right yung car pag dating sa bridge gap
4. I think EPS/steering is ok since wala namang lumalagutok pag sinasagad yung pag ikot ng manibela
5. I noticed the squeaking sound dati, about a month ago, but it disappeared naman that day.
6. vibrations if I am going 100kph and up

tried the bounce test sa front shock absorbers, ok naman, pero I noticed it is somewhat easier for me to do the bounce test kesa dati (to push the front downwards). :twak2:

if shock absorbers ba ang problem, do I need to replace all 4 shock absorbers?
ok ba ang 555 brand? tumatagal ba?

left side picture.. mukhang wet look yung ball joint.


my car is an 2009 Toyota Corolla Altis 1.8V

please help.. :help:

thanks!