03 ex awd cracked rear dif.

Hi I am new to the forumn and tried to search the forumns for an answer and couldnt find anything. Yeasterday while driving the rear wheels on my E locked. I crawled under my E only to find the rear differential is now cracked. Has anyone had this issue in the past? The fluid inside was clean and didnt smell burnt at all. So now I have to replace the whole rear dif. A friend who owns a shop (5 states away) says this rear differnetial is sold as a unit. Can anyone verify this. My local dealer parts department was of no help as they are in the process of upgrading there computers and couldnt give me a price or any information. If it is sold as a 1 piece unit does anyone have a idea of how much it costs? I know prices vary around the country and I am just looking for a ball park figure. Any help or information in this matter would be much appreciated.

Thank you in advance for any help or info in this matter.