I have a 2000 C280 with the m112 and 722.6xx engine and tranny.

Bought used at 36m, 6/2005 and now has 95m.

Very happy with the car an no problems so far with the tranny or engine. Compared to an older 1991 300CE that I have, maintenance has been cheap. Only relatively costly item was a MAF.

Once in a blue moon, the tranny will have a harsh downshift into 1st. This typically would happen on a cold engine while coasting slowly to a stop. We avoid this and also have the tranny in "W" setting all the time, so it rarely happens.