My 2018 3500 Cummings, Aisin 4X2 Dually, is in production and expected mid-November. I will be storing it until March/April 2018. What maintenance is needed, will DEF be OK? Should it be started occasionally? My current '97 I just leave alone until spring and it always started without any problems. Any suggestion going to the 6.7 and 21 years updating from '97 would be appreciated.