18screaminwheels

I really don't understand the reasoning behind New Cars and Trucks especially pickups needing such a low rear end ratio. My 2008 Mustang had 3.55 rears and that was considered a slight performance upgrade. Loooking back I wish I would have got a higer ratio in that car, I rarely drove it like a madman.

3.55 now comes standard on all 4x4 except for the eco which can have 3.31 or something in a 4 x 4. I cannot see a modern 4x4 drivetrain being that innefficient that 3.31 or 3.55 now has to be the new standard. Except for the 3.7 these things put out gobs of torque compared to trucks from the 1990's.

If you plan on towing/hauling a lot and really need 3.73s or lower then fine, by all means get lower gears.

What vexes me is 6 gears in these things now, and except for the 3.7 which actually needs the lower gears I think the 5.0 and Eco could still pull like mad even with high ratios like 2.73 or 3.08. And highway MPGs would certainly go up noticeably I think, not by leaps and bounds, but if you have and engine turning 1800@ 70 MPH vs 2000@ 70 MPH think about how much fuel you could save over 5 years.

In high school I drove a land yacht 1978 Oldsmobile 98 Regency. 4000+ pounds. Oldsmobile 350 V8, 175 HP, 270 Pounds of Torque when new. That car had a 3-speed auto, and 2.65 or so rears if I remember right. That car was 15 years old when I started driving it and still had a lot of life left in it. With that powertrain setup it was no speed demon by modern standards, but could still snap you back in your seat pretty good and burn the tires up. I had a lot of fun back in high school humliating Camaro, Firebird, and Mustangs from that era drivers with their tired old V6 and small V8 motors.

Buyers today are less and less informed about what they are buying and how the specs affect their fuel usage. Some kid from suburbia with stars in his eyes buys an ecoboost 4x4 with 4.11 gears and then comes crying on here about getting 13 MPG when he drives it like his old Honda Civic.

I've ran into some totally clueless dealers/salespeople as well who have no idea what they are selling, I know way more about what they are selling than they do.

I am considering buying a new F150 4x4 right now, I am torn between getting an EB or 5.0. What aggrivates me is the "cookie cutter" way these things are specd and put on dealer lots today. If I want black seats I have to buy an Fx4 or something more expensive. I want a Supercab, but I also want a 3.55 locker, Hell I'd go for a 3.08 locking diff if I could get one, and none of the S-cabs on dealer lots seem to have it, but a lot of - crews do. Bring stuff like this up to dealers and they act like you're from Mars...

acadianbob

I enjoyed your post! Some good observations in there and a lot of truth.

One thing that I might point out is that the axle ratios should also be considered in conjunction with the transmission ratios. In the new 6 speed auto, both 5th and 6th are overdrive ratios. In "the old days", the top tranny ratio was often 1.0, or maybe a slight overdrive.

So, I think you are right essentially. New engines do produce more torque; they can turn slower. While rear axle ratios haven't changed much over the years, I think the transmission ratios have.

Another thought; the towing capabilities are also much higher today. So torque multiplication from lower (higher number) ratios is desirable there.

But you are right when not towing; and many people don't tow. Why not go for the lower numerical ratios and get the mileage.

HoustonRider

As they turn out a truck every minute or so on the assembly line, they are built for the masses. From the guy that tows daily, to the parking lot queens with shiny tires that never see the dirt. Packages keep costs down, so yeah, can't get a loaded platinum with cloth seats or sliver leather. You can build certain trim levels to your satisfaction, but its not like it was 30 years ago.

Hunttman01

...try towing with a low gear ratio... you'll see that a 3:55 or 3:73 is ideal.

Keep in mind there are people who still use trucks as trucks

Mr.Bojangles

I somewhat agree with you. I have the Eco 4x4 with 3.31 and I was able to tow around 6k lbs of my household goods with ease. I know my set up is rated to tow around 9600 lbs, and I feel it should have no problem towing that much. I get around 17 mpg city and 22 mpg highway. Can I accelerate as fast as someone with 3.55 or 3.73 gears? Heck no! Do I need to? No. I don't feel the higher ratios are "needed" for towing, unless you tow a much heavier load or up hills/mtns.

Centexguy

I have the 3.15 rear end in a 2wd. I don't get any better mileage than anyone else here so that logic is out the window.

People like acceleration and speed and fun things to drive. 3.31 or 3.15 gears aren't fun to drive. They suck as a matter of fact.

And anyone who thinks 3.15s or 3.31s will tow like 3.55s or 3.73s really needs to try doing it. Will 3.15s or 3.31s make 10,000lbs move? Yes it will. Will it be hard on the drivetrain and struggle going up hills with 10,000lbs? Absolutely.

Trucks back in the 70s weren't rated for towing the weights that vehicles do these days. Technology has changed, people have changed, needs, wants, desires, priorities, etc. that's why we have trucks with 6 speed transmissions, 450ftlbs of torque, and 3.73 gears. It's as close as we can get to having our cake and eating it to. Unless you're a vegan and then change cake to lettuce.

Thislilfishy

Another note, tires are much larger these days. Seriously, can you think back to the 70's and 80's? When trucks came with 32" (or close) diameter tires? I can't. That adds to the ratio. Just saying. I think the gearing is actually about mileage as well keeping the engines at the most efficient rpm range for EPA listed highway speeds. In the past it was assumed that the lower the revs the less fuel was used (likely true with carbs) which may not be true with precision fuel metering in modern vehicles.

Ian

Mike Up

As much as I dislike this forum, the obvious is being overlooked here.

The truck engines today are required and expected to be able to tow certain weights reliably.

Since todays engines are small displacement, they don't have the cooling properties of a thick walled big block used yesteryear. They also use much higher compression ratios that create a lot more heat in the engine.

To help keep these engines from overheating while doing work, the higher ratio/shorter gears as 3.73 or 3.55 are needed. The lower ratio/taller gears as 3.15 or 3.31 have much lower tow weight capacities but obviously do better with mileage.

Dropping to a 3.55 axle on a Crew Cab 4WD 5.0L will drop tow capacity to an anemic 7700 lbs. Using a 3.73 axle will allow 9300 lbs tow capacity without overloading the engine and drivetrain.

Yesteryear engines had very low compression ratios and very large displacments for their low power output. They also had lower capacity ratings as well.

If I'm going to pay over $25,000 for a truck, I expect it to tow a load greater than a light fiberglass bass boat.

schrod

Well now, I traded my 2011 3.5 ecoboost with max-tow w/3.73 rearend for a 2013 3.5 ecoboost with a 3.31 rearend and regular tow pkg. This was to help improve crappy gas mileage. I still have a GCWR of 15,100 and tow capacity of 9200 in my screw w/145 in wheelbase. This should be more than enough to still pull my 8K travel trailer. Tow pkg includes transmission cooler and heavier radiator cooling just like max-tow. Only thing I don't get are the power tow mirrors. A problem I am alleviating at this very moment.
If the transmission has to stay in 5th gear when towing then maybe it will get even better than the 9.2 ave. I got with the max-tow. This will more than likely keep it out of boost so much which I feel is a problem when towing and the tranny does not want to down shift.

Truck owner

schrod, what crappy gas mileage are u talking about. Max Tow serves its purpose and i would rather have that set up for towing 9k on a regular basis than a 3.31 rear. I guess u will see the diff over time. Good luck with your new truck, hope it serves u well.