Sorento U Joints

I am new to this my dad has a 2004 sorento and i am trying to help him out. he recently replaced the carrier bearing and the other day i crawled under it and it was loose again so i tightened it up and within 3 miles it was making a racket again. so upon further inspection it is the rear u joint. here is the issue i can not get it anywhere but kia and they want over 600 for a whole drive shaft. all i need is a u joint. anyone have the specs i can jsut go get one and put it in. why are these koreans so hard to deal with

thanks

http://www.driveshaftspecialist.com/
Click on import section then Kia They sell rebuilt drive shafts,U-joints and carrier bearings.
$28,95 is close to a parts store price for a u-joint.
http://www.ebay.com/ Search kia sorento U-joints or carrier bearing.
http://www.amazon.com/ Search Kia Sorento U-joint Note not all are the same check for your vehicle.