View 0 Photos View 0 Videos Caterpillar C4.4 Engine Part Control Assembly-NH3 Ammonia Gas Detector Module $200 USD (NEW/ OPEN BOX) Caterpillar C4.4 OEM Diesel Engine Control Assembly-NH3 Ammonia Gas Detector Module, for sale!!!!!! Part #:421-7787; Other Part #: 28344799; Stock #:E4581 For more... ConditionNewPart Number421-7787Stock NumberE4581 MLS Number14450564CategoryEngine Miscellaneous Parts Last Updated6/25/2026 LocationHialeah, FL, US Sold ByJJ Rebuilders Inc. (844) 385-___ SHOWNUMBERCall Seller Email Seller Save More Info