2003 E320 My transmission has a selector for W/S (Winter/Summer). Would there be any long term ill effects to running in W mode full-time? I realize that the car takes off in second gear and I am not a street racer. Just something I was interested in for the longterm of my baby.

 

Part of the following is from earlier posts of mine, last from December.
The "S" stands for summer or sport--take your pick. Depending on your car model and year, the gearbox is driver adaptive and it "remembers" your driving style and adjusts the automatic shifting to your style. In reality, it picks one of several pre-mapped shift sequences (6 or 7 programs) and uses it on an ongoing basis. If you change your style or someone else shares the driving, the program will change accordingly. It won't change instantly but will "adapt" over time. It always starts in first gear.
The "W" stands for winter mode. It always starts in second gear to help in snowy / slippery conditions or lack of traction situations. It is not driver adaptive and only uses one program for all situations and all driving styles. It also makes for a smoother start from a stop, IMO. It tends to even out Stop & Go driving as well. I especially notice on my car that braking is different just as the car stops since it doesn't downshift to first gear.
While I believe you can change on the fly I suggest you only change when fully stopped. It doesn't matter if you use "W" in summer or vice versa.
"W" mode will not affect your transmission if used in any type of weather or road surface. Its just a different program.
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