2005 NA six speed right rear axel CV joint getting noisy, looking to change it out, I see there is a circle clip on the differential splines does this require opening the diff?

 

That small ring sits in a grove very near the end of the splines. It is an open ring like a "C". You do not need to open the differential to remove that ring. Sharply pull the half shaft/axle outward and the ring will collapse into the grove allowing you to continue pulling the half shaft all the way out of the differential housing.
Chrysler has discontinued that ring so hold onto it as you can reuse it if the new half shaft you purchase doesn't come with it.

 

You do not need to open the differential. That ring is spring steel and will collapse into a grove near the end of the splines. Just give the half shaft a sharp pull to collapse that ring as it is shaped like a "C". You can reuse the ring if the new half shaft you purchase doesn't come with a new ring. Chrysler has discontinued the ring for our axle.