Mercedes to merritor swap

Hello all, im currently in a situation where my Mercedes rear differential off of my 2007 coronado (3.58) is starting to show pebble sized metal in the magnet. Sadly all my local shops do not even touch these axles only merritor and eaton. Since buying a rebuilt from freightliner costs an arm and a leg what would be my options as far as swamping them out per say with a junk yard diff?

Some say i need the whole housing, some say i need to find a merritor that fits with the same ratio…Otherw say to swap out both front and rear …

 

Went ahead and pulled the trigger on a set of 20-145s
Will let you know what i run into.