my rotors were warped on my 99 f-250 because i towed without trailer brakes a few times.  they are a must for any truck 1/2 ton or 1 ton.  my old 97 gmc 1/2 ton towed pretty good but it also had the vortec v8 in it.  made sure it is set up right, get a tranny temp gauge and watch it also.