0 Allison 2100HS, , Transmission ECMs, Fits to: GM/Chev (HD) WORKHORSE, (Used) Allison, TRANSMISSION ECM- Model: 2100-2200HS, Part Number: A40004U0, Serial Number: 45004U00018, Serial Number: BK5321N07123Y1GA, For more information about this item, give us a call. We ship Worldwide! (CRG HEAVY TRUCK PARTS) 929 W PULASKI HWY ELKTON, MD 21921, Serial# 45004U00018, Part# A40004U0,