That looks like a Chrysler 9.25" rear end. You have to find where that piece
of metal came from.

This rear uses side adjusters instead of shims, which makes it easy. To
remove the carrier you remove the two 3/8" locks, which will allow you to
loosen the side adjusters (round disk with holes), then unbolt the main
bearing caps and the carrier and ring gear will come out. Also, you will
first need to withdraw the axle shafts. Push in on the axles, then remove
the C-clips inside the spider gears, then pull the axles out.

Tony

I decided to take pictures as I go along. See

http://igor.chudov.com/projects/Automotive/Drivetrain-Noise-In-Dodge-RAM-1500-Pickup/

Some findings as I opened up the differential.

1. It is full of gear oil. (means my oil change 2 years ago was successful)

2. On the bottom there is some amount of of, like, 100 grit metal
dust, settled down.

3. There was one foreign object on the bottom, see

  http://tinyurl.com/zr8zg

4. The gears and such, do not seem to have any unusual damage.

i