View 8 Photos View 0 Videos Jacobsen 40645 Engine Brake for Cummins ISX12 $1,000 USD (GOOD USED) Jacob Rear Assy Jake Brake for Cummins ISX12 Diesel Engine, for sale!!!! Jacob Part #: 40645; Cummins Part #: 4298972; Cummins Supersession Part #'s: 4330981, 4330250; Stock #:... ConditionUsedFits To Make(s)CumminsFits To Model(s)ISX12Part Number40645Stock NumberJB1019 MLS Number13582995CategoryEngine Brakes / Jake Brakes Last Updated5/15/2025 LocationHialeah, FL, US Sold ByJJ Rebuilders Inc. (844) 385-___ SHOWNUMBERCall Seller Email Seller Save More Info