my '19 laramie 1500 4x4 ccsb 5.7 with 3.92 rear end and 33 gal tank and offroad pkg towed our 28' 6000# travel trailer fine. that truck had the 8hp75 tranny with 5.0 first gear and huge brakes so towing was no problem. on mostly flat roads I could set cruise for 68-69 and get 8.5-10 mpg so I wouldnt say 5000# would be the cutoff for a 1500. would just need to be equipped right for the job.
