Question on rear differential on 2010 Ford E350, V10

Does it have a door post sticker. There is a code on there to tell you. Read the axle code, then google it.

If you don't feel like crawling under the MH then take the VIN to the parts counter at a Ford dealership, tell them you weren't provided any documentation on the chassis and would like to know:
1) what transmission that it has
2) the rear differential gear ratio
3) is it a standard differential or limited slip differential

Also go here. On the right side of the screen, enroll. Create an account. Add you vehicle's VIN. Get info, recall and TSB notices on the chassis.
https://owner.ford.com/servlet/ContentServer?pagename=Owner/Page/HomePage