If you don't loose that much = she's very low on ATF! I just finished a side job last weekend (HP24 in an 03 went south). Poor transmission was starved of ATF fluid and it was the incorrect fluid. Owner had a service done a few years ago at an Independent Mercedes shop. I guess they had no clue what to put in it (fluid looked more like syncromesh gear oil vs ATF). Then they had no clue how to properly fill it. Poor HP24 did not have a very happy life after that service that's for sure!

I've now got it back on the road, running and driving excellent again!