1. Don't go to a Chrysler dealership with your Crossfire. They stopped servicing the Crossfire years ago and the fact that it is a Mercedes R170 their techs do not know a thing about it.
2. Best place for service is an independent shop that specializes in European autos with an emphasis on Mercedes.
3. Do you have any maintenance records for your Crossfire? When was the transmission fluid changed?
4. The shop you use must be able to use a scan tool to get into the Mercedes transmission codes; Scan as a 2004 Mercedes SLK 320 if your car is a Limited model. The DTC will tell them how to proceed.
5. To make things simple: Check the electrical connector at the transmission to be certain it has a tight solid connection that isn't leaking. If that has a lot of fluid on it you could replace the o-rings, check the fluid level to be certain it is at the full mark and give it a test ride.

If that fails to correct the problem drop the transmission pan, replace the conductor plate with a new one,and a filter change, refill the transmission and enjoy the ride.