New Expy owner

[Cruk]

A month ago I purchased a 2017 Ford Expedition XLT EL. I have owned several F series trucks over the last few decades but never a full size SUV. It has 125,000 miles and appears to be in very nice condition. I had a pinion seal leak fixed and new parking brake shoes installed. I thought while it was in the shop at the Ford dealership I would get the cooling system flushed and the transmission filter and fluid changed. My first full tank fuel mileage check was 18mpg which I think is great. I really like the vehicle but I do have a few items that concern me. The first is that when backing up my driveway when I just got home the car made a strong shake or shudder and then smoothed out and didn’t do it anymore. The second is my cruise control stopped working, when I press the ON button it won’t turn on. The last thing is There doesn’t seem to be a right side seat belt latch in the third row. I Wouk appreciate some insight from anyone that has had experience with any of these issues. I look forward to swapping experiences with people in this forum.