My garage door opener is about 14 years old. Now, I faced a problem with it. The working condition of the motor is good, but the attached drive sprocket does not turn. I want to just replace the motor and re-attached the existing censors, chain, etc. In this situation. I am a little confused. Can I replace everything or else drive sprocket part only? If anyone had an experience, please share the information. Any kind of suggestions would be appreciated.