Answer
Jun 12, 2026 - 09:49 AM
You’re right that the 66RFE is listed in the fitment details. This ATS Thermal Bypass Valve is compatible with the 66RFE transmission used in the 2017 Ram 2500 6.4L, as well as the 65RFE, 68RFE, and AS69RC units. The confusion comes from the catalog focusing on Cummins applications, but if your truck is confirmed to have the factory 66RFE, this kit will fit and function correctly on your Ram 2500.
