* 6-speed automatic (68RFE): This was a common transmission for several years.
* 6-speed manual (NSG370): Manual transmissions were offered, but less common than automatics.
* 68RFE with various updates: The 68RFE was refined and improved over the years.
* 8-speed automatic (8HP70): More recent models have used this transmission.
To know the exact transmission in a specific Dodge Ram 2500 diesel truck, you need to provide the model year.