Not only do I change the oil and oil filter, but also the air, fuel, oil, and trans filters, trans fluid, differential fluid, grease all the fittings, and adjust the valves. My experience with Freightliner dealers is they do not do all the work the claim to have performed and billed. A couple of major items is they did not adjust the valves, but charged for it, changed the trans fluid from synthetic to mineral based (I did not ask them to service the trans, but they did anyway), yes I got charged. The last time I went to a Freightliner dealer I was out of town and had the coolant changed. A week later the transcooler developed a leak. When I picked up the coach with the new transcooler the oil line between the engine oil pump and injector pump was disconnected. There was no reason to have disconnected that oil line.
My recommendation is do all the service you can or find someone you can trust.
