I have a 1996 Saturn with dual cam engine with 157,000 miles. The Saturn had the check engine light come on and I have been told that the code means the car has a 3rd gear differential transmission problem and that it needs a new or rebuilt transmission. Given the age and mileage of the car is it worth replacing the transmission? Is the error message 3rd gear differential mean just the 3rd gear of the transmission is gone? How much would it cost to replace the transmission with a new or rebuilt one?