i have a 2005 2500 hd duramax ext cab and the passanger side rear door latch
makes a rubbing sound when hitting bumps, i greased the latch and noise went
away for about 1000 miles, anyone else having this problem, any advice on
fixing problem or should i just take it to dealer?

both my rear doors did this.. I adjusted the latch inside the door jam area so it would be tighter when it shut. Both shut and do not rattle or rub any longer. I also had this on my 03 HD as well, seems to be pretty common.