68-RFE Trans Cooler Bypass Block, Fits 2013 and Up Cummins with 68-RFE or Aisin AS69RC Transmission. This is a Must for any truck that has a 68-RFE or Aisin AS69RC transmission in it. Dodge decides to incorporate a transmission cooler by pass valve into the cooling system of the 68-RFE and Aisin AS69RC that bypasses the transmission cooler during cold operation.