I've been using Phillips 66 Guardol ECT 15w40 in my Detroit Series 60 motor since last Spring. I have my pm's done roughly every 15,000 miles.
I just bought 10 gallons of Guardol ECT 10W30 for the upcoming winter months, which I'll be running from mid to late November until late March.
For filters, I've used Fleetguard, Baldwin, and Detroit branded filters, which I've been told are made by Donaldson. I've found a local shop that gives me the lowest prices on Detroit filters that I've found anywhere, -cheaper than Fleetguard, Baldwin, or Donaldson, so I'll be using them from now on.