Coming up on 200k miles on my Expedition. Trying to find out what services i should be concerned about. I was also wandering if it would be benefitial to do an engine and transmission overhaul. Just looking at preventative mantenance. I am having issues the heater and A/C. Going to flush and fill radiatior, but not sure what to do about the A/C. Also measured standing heighth of my truck, because it looked like it was leaning. Driver side was 1 1/2 inches highter than the passenger side on front and back.

 

If the engine and trans are running fine, I wouldn't worry about anything other than standard servicing such as fluid and filter changes and maybe a PCV valve for the engine.
The heat/a/c issue could be a blend door issue in the dash. Quite common on newer cars.

Not sure on the leaning, could be worn springs or body bushings.
I have moved this to the Expy forum since you have more than just engine issues and you will get better responses.

 

No worries until something happens. Change the tranny fluid every 35k. They need regular help and I think you have a 4r 70/5 and maintenance is a must. Plugs every 100k. COP's as necessary, no big deal here until a misfire.
If not the original alternator, that will be going soon but no worries, easy to change.
Check you rear end wheel seals as they last about 200k.
Change out your radiator hoses and new anti freeze and drive baby drive!