if you bought a new truck

is there a break-in for the axles, differential, bearings, or something that they are worried about?

 

so, changing oil for both eng and rear axle, sooner than the recommended interval in this case because of the long drive, or just in general for something new?

iirc, 7500 miles or something was thrown out there as a first oil change. i would think changing sooner would be better.

never though about it before, but i have always bought used. this is a first new modern truck.

 

And expensive to fix...

 

Some axle manufacturers do have break in periods. American axle had a break in on the rear axle of my 2500 a few years ago, no towing for 500 miles. Hypoid gears slide against each other so clean oil is a great thing and they never get changed, even though some claim they are "lubed for life". Its never the case. I, personally, like changing it for the first time a few thousand to get and large contaminant out as there is no filters and nothing really protecting other components from the crap in the oil. Usually when we rebuild a rear end it takes 3-4 cans of brake clean to remove the deposits left inside the axle housing and axle tubes.

It may be my piece of mind but I change a new engine oil at 1000 or so. I've torn filters open and have found chunks of alumn. castings, some sandy materials etc. Obviously the filter did its job but for my own feel good I do it earlier the first time always. You probably will never have an issue if you don't, but at least change it on time. Seems people cant manage that even now a days. You don't "have" to do it early. But at least change the axle oil once or twice in 100k miles.