The transmission got a so called modulator, they can be adjusted to make shifts firmer, I guess people have had problems with them, MB have redesigned them servers times, the new one is green and has a thin stick thing inside to make adjustments easier and external.
You can also buy a superior shift kit(some springs for mounting inside the trans) they solve issues with flaring and hard shifts, and can serve as an upgrade too.

Don't know if that helps ya