What Steve is trying to tell you is not to monkey around with a $5000 transmission. AutoZone won't have the capability to provide a diagnosis, and you're not capable of sorting this out at home.
Take the car to an MB dealer or indie that has the capability of providing a real diagnosis of the problem. There are some "known" problems with the early 722.6 units, and only an experienced MB tech will be able to pinpoint the problem and provide a solution.
Something is amiss. Erasing the codes won't fix the problem. The codes are simply a storage of an event. You might be able to get the car out of limp-home, but why bother? If something is wrong, it will still be wrong. You could be contributing to the demise of a very expensive driveline part. You are going to have to bite the bullet and hire some expertise. On the forum, we may be able to provide some feedback as you go through the process, but an actual diagnosis is unlikely here, as we cannot touch the car.
1998 C230 "Black Betty"