F150 3.31 gears vs 3.55 gears

I can not say for all model years in question, but Ford Trailer Tow Packages usually come with an upgraded radiator and transmission cooler. IMHO, those a key to engine and transmission longevity.

You would definitely be better off with the 10 speed transmission.

Now, you're looking for as old as 2015 models? 6 speed will not cover up the higher gearing as well as the newer 10 speeds.
And the older model will have a few less ponies.

Yep... Even with my 3.73's I always lock out 6th gear.. and that's just cruising on the flats..

Up the grades, it likes 4th. Even just some of those gradual inclines, I'll manually shift to 4th.

Since I have the Ecoboost, if you give the engine some beans, the boost goes WAY UP. If you are only chugging along at <2000 rpms, you can be pushing some 10+ psi of boost and not even see any speed increase! Plus, the temps start to rise pretty fast..

Bump it into 4th, and the boost goes down to arouund 5 psi and you actually pick up speed and keep temps in check and actually get better mpg's..

That's why running in 5th is better than 6th when towing. Going the same speed, there is at least a +- 4 psi boost difference running in 6th compared to 5th and temps increase and mpg's drop running in 6th. (while towing... )

I didn't find any of this out until I got an ODB2 plug in and phone app to monitor a ton of sensors that the dash does not even come close to showing you...

Anyway, the OP wants a 5.O V8, so a different beast than my Ecoboost, but I would not want that 5.0 towing my little #7000 TT.. :)

Mitch

I agree with Mitch…3.55 if the F150 has a six speed transmission.

I'd always get the lower gear (3.55) for towing.
My 2500 Suburban has 3.73 and I wish it had 4.10. I've found if I put it in 5th gear instead of 6th it just tows a lot better, both up hill and down hill.

Depends... I think after 2018, the F150's came with the 10 speed trans as opposed to the 6 speed trans..

So, if that's the case, get the 3.55's if it's 6 speed.. I think from 15 on, that's all you can get in one, except if you find a HDPP (Heavy Duty Payload Package), but those are like Unicorns in the wild. (not very many, and if you find one, will cost lots of $$.. )

For the 10 speeds, I think you could get away with the 3.31's.. But, I'd still want some 3.55's with the 10 speed too, if you are going to be towing that heavy..

I have 3.73's with a 13 F150, but that's a different apple compared to the 15 and up F150's, so can't really compare, other than the Ecoboost and the 6 speed trans for the most part.

Oh, I see you are looking for 5.oh no's... Okay, I don't have any experience with those, other than they are not the 'top' engine option for the F150's in general... :)

Good luck! Mitch