Please Help. SPN-4364.

Thanks for the update. "The metal gasket that came with the new doser was wrong." Curious, was the part OEM, come from Navistar dealer? This type of thing is not uncommon with aftermarket parts. People in the know (shop owners, techs) most will tell you never use aftermarket parts especially with anything emissions or computer related. Sometimes that may be the only thing available. Some don't want to pay the higher cost of OEM but too many times aftermarket will bite you, costing time, headache and $. FYI - there is more than meets the eye to the DEF. Not just the doser but pump, pressure sensor, module/controller, wiring.