I tow with an 05 nissan titan. per the manual, overdrive is ok with use of tow/haul mode. I sit at about 2k rpm at 75mph, from laurel to summit point average 13mpg on 87octane. Transmission temps are fine. tahst a 1200# trailer with a 2300# car and maybe 400-500# of stuff in the bed and cab.

think the titan big tow uses a 4.10 final. But its a 5 speed gear drive automatic trans, I think the older belt based automatics where the worst as far as building up and having issues once they get hot.