I have a 84 Dodge Ram Van 250, with a 318, 4dbl carb, posi rearend, 3speed trany. I don't get good gas miliage, but was wondering if I could instal a newer trany on it like a 4 speed?, wat would I have to do to complete the change if I can?

 

Did you investigate to see what transmissions were available for your van in 1984? Lots of things affect gas mileage. Rear end gears are one of them. When you start messing with Transmissions, you have to take in consideration, bolt up patterns, transmission mounts, drive-shaft lengths, and electrical and other requirements. In other words it will probably end up causing you several headaches, and costing you more money than its worth in the long run. Take into consideration the time and effort it will take to source the parts and perform the labor and you might end up paying less for the extra fuel you use then the conversion you are asking about.

Hope this helps,

Jason