I regularly tow 5-6k with my truck. It’s a 5.0 TBI with NV3500 and I believe 3.42 gears. All original with 260k on them all. Truck is happy with it if you keep the revs above 2k. Highway driving is in 4th gear. No faster than about 65.
Mind you these heavier trailers have brakes(surge). They also aren’t big campers with lots of wind resistance. I do also tow around my utility trailer and flat tow cars in the 2-4K range with no extra brakes. Still drives fine, just be aware of the extra braking distance of course.
I love towing with the manual. So much better control, especially down long grades. So sad manual trucks barely exist anymore in this day and age.
Mind you these heavier trailers have brakes(surge). They also aren’t big campers with lots of wind resistance. I do also tow around my utility trailer and flat tow cars in the 2-4K range with no extra brakes. Still drives fine, just be aware of the extra braking distance of course.
I love towing with the manual. So much better control, especially down long grades. So sad manual trucks barely exist anymore in this day and age.