3.55 or higher. 3.73s would be ideal.

 

I guess, but quickie mental math tells me that a 5% difference in RPMs won’t make a flip of difference between two otherwise equally optioned trucks. That’s 2,000 vs 2,100 RPMs in this scenario. Or 3,000 vs 3,150 if you’re pulling a bit harder. You get the idea.

That doesn’t matter much when we have cool tricks like sport mode, tow/haul and manual shift to make magic happen now.

Anyway, 3.73s are usually some heavier 9.75” axle (HDPP package) and that’s where the fun begins. Some trucks have 3.55s as a Super 8.8” rear. See non-tow package 3.3 trucks. Look at the towing guide online and you will see the drastic GCWR differences. We get the “If I swap to 3.73 gears, do I get higher tow ratings?” questions every now and then. If only axle gears were the reason for that rating on its own...

 

I had the 3:55 in my 2018 F150 and 10 speed 35" tires. I did tow a 6K lb boat and it was a dog. Constantly shifting and mpg was garbage. Swapped out the 3:55 to the 4:30 and am definitely happy I did. Even daily driving is better and improved mpg a mile or two. I didnt do the math but I assumed I'm around a 3:73 equivalent with 35" tires.