The break in is mostly for towing on new trucks and it's in the manual not to tow before 1000 mi usually. If you want to tow or plow snow or other stress before that, it's up to you. These trucks have EDR Event Data Recording and they would check it if you brought it in for repairs. There are ways to detect loads and possibly when connector was used. Other than that we do just get in and drive.
All of the major gear MFG and sellers have this same warning I linked. Leaning towards towing but it says do the procedure and "Failure to properly break-in a new gear set can be identified by inspection, and may void the manufacturer’s warranty."
All this is up to the owner/buyer. Just wanted to inform that it is part of the "warranty". The gears will be soft annealed (lose hardness) if over heated. They must heat and cool a few times in the oil of the diff. until "broke in". (I.E. work harden under normal road load)
The gears in new trucks will be of higher quality (tolerance) than aftermarket.
My 1997 F150 has 275,000 mi. Still running on orig transmission, transfer case, differential. Chevy and Dodge will have same quality gears or better.
