I currently Have enjoyed 10+ years with my Ranger4x4 sport- 4.0 which has 110K miles on it
I just installed a new Waterpump ,A/C compressor and Condenser kit and will be charging the A/C soon.
The truck had a new trans installed at 70K and plugs and wires at 90K
i,m looking to hook up a scanner and look at the info /Performance details for further Spring Maint
what numbers are normal or Important at this point and Time (don't want to get too deep in the weeds)

 

At 100k miles I would replace the 2 long chain tensioners, just as general maintenance
Use motorcraft only tensioners

I would also think about changing the 2 Upstream O2 sensors they use up their chemicals after 100+ K miles or 12 years, if you have noticed a bit of a drop in MPG then for sure do it sooner that later
Also change fuel filter every 5 years or so

The computer has all the data parameters for the sensors so will notify driver by turning on the CEL(check engine light) if there is a problem with any "numbers"
So not sure what "numbers" you would want to look at
The BlueTooth OBD2 scanners are good to use to watch Live Data on your phone while driving, that's when you can see whats what with the "numbers"

I just got a BlueDriver unit and have no complaints, used it on 6 different vehicles so far and worked fine, also reads transmission codes which some do not do

 

I did order 2 chain tensioners from Rock auto ,but have not installed them yet.
I currently have no CEI lights and just passed 2 yr inspection.My intention is to get ALL Fluids Changed NEXT including transfer case and differential.
I think I owe that to this Truck for it s Years of Service.
Suugestion are appreciated

 

My Concern will be when I replace the A/C accumulator and metering valve.
I,m not sure what total quantity of oil should be in the system and Have not seen much so far ,,out of the condenser and the compressor which was replaced this week