(Used) 2018 Allison (AT), TRANSMISSION OIL COOLER- Part Number: F31-6187 REV E / 21324AA-11-17, Model: 2500RDS, Serial number: 6311611166, Engine: PACCAR PX-7, Reference images for condition For more information about this item, give us a call. We ship Worldwide! (CRG HEAVY TRUCK PARTS) 929 W PULASKI HWY, ELKTON, MD 21921