I just stumbled upon this and pulled it from Nissanhelp. Note: It's not a recall service campaign, it is just a service campaign.
http://x.nissanhelp.com/forums....html
Nissanhelp.com wrote:Description: 2009 NISSAN ALTIMA, MAXIMA; VOLUNTARY SERVICE CAMPAIGN LEFT REAR SUSPENSION KNUCKLE
On some 2009 Altima and Maxima vehicles, the left hand rear suspension knuckle may not be manufactured to specification, which may result in noise or vibration under certain circumstances. Although no safety issue is presented, Nissan is conducting this service campaign to identify and replace those affected units. This service will be performed at no cost for parts or labor.