If your tranny has the W/S rocker switch, then you have 1st gear start in S(ummer) mode and 2nd gear start in W(inter) mode. Are you saying the shift lever does not physically seat itself completely in the D slot? If this is the case I would check the linkage under the car. A missing bushing or remnant of a bushing will be obvious.

glenmore
1991 300CE
2000 C280