I think the Aisin has a lower ratio in the transmission. If you feel ok towing with your truck stock, I'm sure it's fine. Tons of guys here towing with stock gears. I'm on 35's so my issue is that I reduced my ratio even further by having slightly larger tires. Additionally, I had 37's and 4.56's on my 2010, which to me was the perfect ratio, as I used my truck for primarily towing.My '17 with the Aisin and 20" factory wheels has 3.42 because it is SRW. I see now on the '19s you have a choice again. I pull a 39 foot 5'er @ about 16k pounds. I haven't noticed an issue yet, but I also haven't towed it anywhere but the plains so I haven't challenged the truck on any mountain grades (yet). Would a move to 4.11 be advised/beneficial to me?