Towed with a 2011 Ford explorer with the 3.5 V6 non aspirated. camper was 3500 lbs. Did better than the hemi 2005 dodge ram it replaced.
just turned 100k last week. still going strong. Now I do not tow anything after I got the tundra 3 years ago,
it carried the family of 4, mother in law , bikes on the rack and the 3 rd full of camping stuff and towed our 3500 lbs popup fine a few thousand miles a year for some time. Mine did not have the tow package. the tow package gave oil cooler, tow haul button to lock 6th out . SO I would put in 5 in the gear selector and lock out the 6th. It never got hot to put a oil cooler even no 100 plus days towing and loaded for camping .