Date registered: Jan 2014
Vehicle: 2008 AMG CLK63 Conv., 2012 R350 4-Matic, Wife's 2015 C300 sedan
Location: Cypress Texas
Mentioned: 7 Post(s)
Quoted: 2605 Post(s)
Over five grand for a transfer case!
Unless you can find one on Fleabay for a decent price you're probably looking at more than the car is worth to replace it.
You might find one off the same model year ML350 fits. They'll be a lot easier to come by as the ML sold well, and the R didn't.