Some good independents or dealers may do this repair in house. I did 2 last week. I have done 100's with no problems. The problem is the drive gear does not hold the driveshaft tightly and slips off. What we do is put a small tick in it and press the shaft back in.
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM