4.30 vs 3.73?
 

Looking at getting my first gasser in a LONG time. What are the general guidelines for ratio selection with the 6.2? I have been reading everything posted on the 6.2 and axle ratios and it seems there is a slight preference overall for the 4.30 ratio; however then I will read some guy tows 10k+ with his 3.73 and no problem whatsoever... then there are the threads where they say they are towing 12000+ over the Rocky Mountains and don't state what axle ratio their truck is. Etc etc.


I was looking at ordering a 2018 F350 XLT CCSB with 6.2 / 4.30 axles. I have a fifth wheel weighing 9000+, a technical poling skiff weighs around 1500, and a utility trailer a couple thousand maybe. So I really don't have anything just massively heavy to move. What would be the most a 6.2 with 3.73 be comfortable towing? Lots of highway running light truck so I was thinking if I did get the 4.30 I could go with a little larger tires, or would it be better to just go with the 3.73?


Cannot even think about a diesel with EGR. And besides tired of the maintenance costs etc. General guidelines from you guys much appreciated and would help many noobs trying to make the same decisions etc.

Depends how much you're towing. I'm well within the limits of an F150. So my F250 with 3.73 does fine. It's not like the old days where we only had a 3 or 4 speed transmission. The 3.73 trucks just spend more time in a gear lower than the 4.30 trucks with todays 6 speeds.

Maybe if I was towing over 9000# I'd want 4.30. Towing that, and 33-34" tires, 295/70r17, I'd rather have 4.56. If I regear I'm going 4.56 or 4.88 (37" tire). I'm not voting, because 4.56 is likely the correct answer.

Understood. Thanx

4.30 all day long. Only time you'd suffer a mileage hit is on the highway.

:-duel1 Humm......easy choice for me because I've had both.
3.73 = diesel
4.30= gas

When I test drove a Superduty off the lot (3.73), I thought the rpm's were too low. Ordered the 4.30 in my 2016 and am not disappointed. Tow a 32' Jayco tag and 5x10, 10k dump trailer. Most of the miles are highway at about 50 miles per day to work and back on the interstate.

4.30 it is then.

If your ordering a truck with 17" wheels and plan on keeping the stock size tires, then 3.73 is a pretty good gear. You will get optimal fuel mileage, and it will tow you 9k fairly well. Obviously 4.30 would tow it a little better.

If your ordering a truck with 18 or 20" wheels, which come with larger diameter tires, or plan on running 35's or close to them, 110% without a doubt, order 4.30's. Your fuel mileage will not suffer(may actually do better) and it will make a big difference in your towing experience.

Ordered with 3.73 with 18" steelies - no regrets. Get what works for you.

I ordered mine with 3.73's. I'm completely satisfied.

my opinion.

if you run mountains... 4.30's no question.

my truck.. 2012 6.2L, 3.73.. 156,000 miles

I carry 1,500 pounds in bed of truck AND tow a travel trailer over 9,000 pounds... and 12 feet high.....

in West Virginia.. a few times on the freeway.. I was in second gear doing over 4,000 rpms... but HAD NO ISSUES.. the 6.2L loves to spin.. so let it.

I have the stock 17's steel wheels and stock size tires...

I did not vote.
.

Isn't the 6th gear in 3.73 virtually the same as 5th in the 4.3? So it's like having an extra overdrive gear for when you're not towing and if you're buying a gas rig you're not towing that much so the 3.73 make the most sense unless you plan to put huge tires on it or modify the height of the truck.

That's my experience. I'm towing in 3rd and 4th in the hills when I'm heavy. 5th and 6th are locked out until I'm on flat ground.

When I have six gears to play with, advantage 3.73. Until there's an expensive huge TT in my back yard.

When I ordered mine I knew I wanted the 275/70-18's for payload and those are 33's so the 4.30 was a must since that brings the effective ratio to 4.10ish over the smaller stock 17" wheel. I don't tow real heavy but tow quite a bit and all of my previous HD rigs all had 4.10's. We've got a 5500lb boat, 1800lb ute trailer, and 9000lb-ish 32' travel trailer and it all pulls easy. The TT is no problem and I don't feel in the least bit under powered. It boils down to your need and use. I've said it before, if 4.56's were optional, I'd get those.

MPG's are not a huge concern to me since I'd rather have more grunt. My 6.2 truck gets the same MPG's as the 7.3 I got rid of and gas is 10cents/gal less in these parts.

No. Even with the RPMs exactly the same, there is a mechanical advantage with the lower gearing.

On top of that, with 3.73's, I was almost always in manual mode to prevent a down shift. With my 4.88's(effectively 4.30's because of my tire size), I still use manual mode in the hills, but I try to incorporate tow/haul more often in the rolling hills. The difference is the torque converter will not unlock in manual mode.