Be sure also that you don't overfill the trans fluid! Check the car with the engine running, when it's plenty warm, and on level ground. If you have any other questions with problems you encounter while using the dipstick, you should do a search; this has been discussed in depth!
Also, when was the last time your trans fluid and filter were changed? If you don't know, change it ASAP!
And another thing, you can adjust your transmission using the Bowden cable (shift times... IE hold on to each gear longer) or you can adjust the vacuum modulator, to firm up or soften shifts a bit. If you do a search on this, I am sure you will find most of the questions you have. Good luck!
2006 E350 w/ 155k miles (Daily Driver)
1993 300E 3.2L Sedan w/ close to about 300k miles
2003 E500 Brilliant Silver (Had 217k miles when totalled!)
1989 300E with 289,000 miles (had for <1 yr while in HI)
03 CLK 500 cabrio (Mom's)
2006 C230k (Dad's)
1999 S420 (Mom's/Dad's)
2000 C230k Sport sedans
2001 CLK320 Cabrio (Mom's)
1995 C280 My First Mercedes-Benz... (155k miles. EXCEPTIONAL AUTOMOBILE. Was Very hard to let go of!)