towing with a chevy 2500HD gas 6.0L

[E Rod]

I had a GMC extended cab with the 6.0 and 3.73 axle ratio. It pulled my Laredo 30 ft ok on flat but a whole different story going uphill or coming downhill. RPM's go up high when climbing a step hill, transmission downshifts and it sound as if either engine or tranny are going to explode. Now I have a 2018 F350 and a 40 ft Alpine that now is a joy to drive. No more white knuckle situations. if possible I would go diesel even if used.