Hello, so I recently bought a 04 GMC XUV SLE 4.2 and after buying it, there was a rattling noise. When I lifted my car, there was something that looks like a babies' version of a differential case on the driver's side front lower control arm. I tried looking online at what it was but couldn't find anything. The closest thing i was able to find was a "Differential Carrier-Carrier Case Front Yukon Gear YC G46002013" on ebay. They look the same but has a big gear on one of the sides like a real differential. Taking a closer look, there were no axle and housing when I looked behind the tire hub on both sides. There is just a rod that spins freely with no resistance. I'm planning to take the housing and axle from my old envoy into the xuv but don't know what that mini differential is for or if it's needed for the 4x4 to work. Does anyone know what it is? Thanks!