So got my truck back, and yes a new driveshaft fixed the issue. The leaf springs were both replaced as part of the "process". But the service manager who was great to work with also said the greasing of the slip yoke is a temporary fix, so they replace the drive shaft. The service manager was MUCH more aware of Tremor issues than my service advisor. They also replaced my door seal for the flapping at 76-82mph. I haven't been back on the freeway to test it so I'm hoping that is fixed. But yes, I can lube my own slip yoke. But I didn't buy a 65k truck to have to lube a slip yoke every 5-10K miles. Changing oil, oil/air/cabin filters...yeah, that's fine. But should it come back with the new driveshaft then I'm going probably going to push for a lemon law. Plus other things happened I don't want to get into on the forum in case someone is reading this from the dealer, as I know a guy that works there has a Tremor as well.