Towing with a new vehicle

[Shogun]

Ok, it appears I may be closer to a new vehicle for daily use.

Either a 2015 F150 with the 5.0 or Chevy 1500 with the 5.3. Either would be new off the lot.

We are planning a holiday where we would be towing our 32' 7000lb trailer for over 2000km on the interstates and other highways.

There is a possibility the new vehicle will be available before our trip. That would only allow for a few weeks.

I have my V10 F350 still so my thinking is that it would be better to get a few thousand kilometers on the new truck before thinking about doing any serious towing with it. Therefore I am looking at 28-35 l/100km or 6-8 mpg towing. Ouch...

What is the current wisdom on breaking in a motor/drivetrain before towing?

[Ductape]

It has been my experience that towing mpg is determined by the trailer and speed. Same mileage; V6-8-10.
I only see gains when not towing with the smaller TV.

[APT]

Most of today's state the same as Hondavalk, wait 500 miles before towing. This is mainly for the differential gears to wear in.

[Hondavalk]

Break in period

Do not tow a trailer during the first 800
km (500 miles).

From my Tundras manual. Assume there pretty much all the same