Hannibal wrote:
First time I've ever heard of a blown head gasket due to a waste gate sticking at idle not releasing the pressure.
My 2010 F250 has tow/haul mode but no means of locking out 5th (O/D). It shifts in and out of 5th as conditions allow. Some might interpret this as constantly shifting. It's been doing this for 96k miles and no damage done. You should see how often it shifts in town. All the way to 1st when I stop. Something is definitely wrong.
Good point. If one is pulling with a manual transmission and was continually shifting from 6th to 5th there would be no concern at all. I have towed with the 5 litre, good engine for towing. I have towed with the Ecoboost, unbelievable engine for towing.