01-26-2015, 09:27 PM
Doug, your filter has a 25,000 mile or one year replacement schedule.. You most likely won't have to deal with it unless you pick up a slug of water somewhere.. Don't think additives will hurt or the ATF.. I Was thinking warranty.. You should have online access to Cummins service info.. I would just check it out.. The DEF is a after treatment... Just saying...
Jimmy