Possible Original Transmissions & Interchangeable Options:
* Three-speed automatic (727 Torqueflite): This is a very common and robust transmission for that era. Many 727s from similar-year Chrysler products (Dodge, Plymouth, etc.) with similar engine sizes should be interchangeable. However, the exact bolt pattern, length, and output shaft may vary slightly, requiring adapter plates or modifications in some cases.
* Three-speed manual (A833): Less common than the 727 in that application, but still possible. Finding a compatible A833 might be more challenging. Again, minor differences in the bellhousing might require adaptation.
* Four-speed manual (A904): While less likely as a factory option with the 318, it is still possible. Compatibility would depend on bellhousing and output shaft configurations.
Before swapping any transmission:
1. Identify your current transmission: The tag on the transmission will be crucial.
2. Research compatibility: Once you know the model, check the bellhousing bolt pattern, output shaft length and spline count, and overall transmission length to ensure it fits your D100's engine and driveshaft. Online forums dedicated to classic Dodge trucks will be invaluable.
3. Consider the driveshaft: A different transmission length often requires a driveshaft modification or replacement.
4. Professional help: Transmission swaps are complex. Unless you have significant mechanical experience, it's best to seek professional assistance.
In short, while some transmissions are *potentially* interchangeable, finding the exact match or assessing compatibility requires a detailed examination of your truck and the potential replacement transmission. Don't assume anything – always double-check.
