hard downshift when slowing down to stop

What is your question?

Transmission seems to be stuck in S mode (standard) I hit the w/s switch to winter mode but still shifting at high rpm's and hard downshift when slowing down to stop...almost like a jolt. After turning off car...then starting again. Transmission defaults back to S mode even though it was in W mode when I turned it off. Any ideas?

What makes this problem better or worse?

seems to be the same weather in W or S mode

How long has your 2000 Mercedes-Benz S430 had this problem?

few weeks