My 92 500 SEL with the 722.370 trans started clicking in reverse about 90K, I took it to the dealer and they did not find any residue in the pan. This continued for about a year maybe more when it started to lurch and hesitate going into reverse when hot. The opinions from various shops was "front clutch", back to MB again and they confirmed the opinions. They dont rebuild transmissions, so a MB factory rebuilt $3,200, 2 year 24K mile warranty, it did not need a converter.
btw, that trans is a handfull if you dont have the proper tools to help you