Migrate vehicle project from 4.26 to 5.1

Hi everyone

I’m trying to migrate a project that is using he Traffic Vehicle System plugin. The plugin uses the vehicle system from UE. All my cars are based on this. I initially created the project in UE4.26. After migrating to 5.1 it says that it cannot find the outer class, which is the vehicle class from UE4.26. I have activated the chaos vehicle plugin in UE5.1 and cloned it afterwards. Still - the same error.

Is there a solution or is the new vehicle system just too different? If so, can the system from UE4.26 be migratet to 5.1 and get it working?

Thanks to all!