I'm afraid we really don't have enough information to help you.
We have to assume that the new drive isn't configured the same as your old one. Are both the new and old drives the same model and version? (There are different models of Delta Servos that are the same size and look simular, but the motors from an older one are not compatible with a newer drive or vice versa.)
Do you have a back up of all of the parameters from the old drive? Assuming that your new drive is the same model as the old one, you would need to load the parameter settings from the old one to the new one in order for it to behave as before. If you don't have either a software backup of the parameters, or written down paper copy of the parameter settings, then you will have to figure out what they need to be. We can't really help you with that though unless you tell us how the motor/drivev is mis behaving.
