I document things that would affect warranty, like motor oil and filter. Rear diff I did not, because Ford doesn't specify a change until 150,000, and I don't want to give any excuse for denying a warranty claim (i.e. you must have used the wrong oil, etc). I maintain separate complete records in an app called AUTOsist on my phone.Since my truck has 13K miles and it's mostly been towing a 3800 lb. travel trailer for most of those miles, and because it looks like an easy-peasy DIY, I am going to change the fluid in the rear differential. That's a start.
For those who have done this and other fluid changes, do you document those in your FordPass app?
I did an oil/filter change and did. Took pictures of the oil and filter plus the dated receipt and uploaded them.