Most other car manufacturers specify measuring trans fluid when warm. Mercedes has tick marks on the dipstick calibrated to temperature for the benefit of those people that can judge the temperature of trans fluid.

I don't know how to comment on the excessive fluid expansion effect you're noticing. Perhaps your transmission is seeing extreme temperatures.

I recommend you check the fluid after a long drive. Until then make sure the fluid is at least up to the cold mark.

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95 E320 Cabriolet, 169K