I checked the differential in my sister's 300TE the other day(just because), and it was a 3.27 indeed. I don't even know if the gearing ratios are the same. TC lockup must occur at a greater speed than my SE, or perhaps the speedometer is off.
1987 300SDL (324000)
1986 Porsche 951 (944 Turbo) (166000)
1978 Porsche 924 (99000)
1996 Nissan Pathfinder R50 (201000)