F-350 with 3.31 Rear Axle

[jmanflyboy]

I've been looking to buy a 2014 F-350 4x2 SRW 6.7L diesel. It only comes with a 3.31 rear. I'll be towing no more than 11K every couple of weeks and was wondering if I should have a concern with a 3.31 setup. I don't want a 4x4, but always thought a 3.73 or 3.55 was they way to go. Since those aren't options, will this be a problem?

[D Lindy]

Look up the specs on the truck and see what it shows as towing capacity and GVW.

[TXiceman]

It will pull the weight, but the axle ratio is too high. That is a highway gear for fuel economy. The 6 speed auto is a double overdrive.

Pulling weight and in hills, it will be down shifting into lower gears to pull. I'd want a lower axle ratio for towing. My 2012 F35 DRW has 3.73 gears and pulls like a pair of mules.

Ken

[RustyJC]

Blame the EPA's corporate average fuel economy (CAFE) standards that the manufacturers are struggling with. The 2014 Ram single rear wheel (SRW) 2500 and 3500 Cummins-powered pickups are only available with a 3.42 axle ratio for this reason. The 3500 DRW (dually) trucks are available with 3.42, 3.73 or 4.10 axle ratios. It's pretty obvious which truck is configured for towing heavy 5th wheels.

Rusty

[golfmedik]

The SRW wheel trucks come with the 3.31 or the 3.55 due to their tire sizes. The DRWs come with 3.73 or 4.10/4.30s if ordered. With the 6.7L, the 3.31s in that truck will pull that weight like it's not even there.

[1olcatonr]

I have 2012 350 srw with 3.31 towing about 13000lbs. The truck is rated to tow 16500. It does shift occasionally but the 6 speed is so smooth you won't feel it. With all the power under the hood this is really a pretty good set up. 11mpg towing 16 everyday 20 hiway. Hook it up set the cruise on 65 and enjoy the ride.

[SmokeyWren]

Originally Posted by jmanflyboy

I've been looking to buy a 2014 F-350 4x2 SRW 6.7L diesel. It only comes with a 3.31 rear.

Correct. 3.55 ratio is available on the 4x4 SRW, but not on the 4x2.

I'll be towing no more than 11K every couple of weeks and was wondering if I should have a concern with a 3.31 setup. I don't want a 4x4, but always thought a 3.73 or 3.55 was they way to go. Since those aren't options, will this be a problem?

You'll be fine. The GCWR is 23,500 pounds, and Ford is good about posting accurate GCWR numbers. With an 11k trailer, your wet and loaded tow vehicle would have to gross 12,500 pounds before you ran into the GCWR. The average wet and loaded 4x2 PowerStroke CrewCab is going to gross less than 10k, probably less than 9k, before you tie onto the trailer, so pulling power won't be a problem.

Your only concern will be hitch weight. The SRW dragging a 5er will hit the GVWR long before it meets the GCWR. An 11k 5er could have about 2,200 pounds hitch weight. 11,500 GVWR minus 2,200 pounds = 9,300 pounds max wet and loaded weight of the F-350 SRW before you're overloaded. That should be plenty of insurance to keep you below the GVWR unless your estimated weight of the 11k 5er was off in the weeds, or you load the F-350 with a cab full of NFL linebackers along with a very heavy toolbox.

[JIMNLIN]

Ford gives the F350 SRW 3.31 2wd or 3.55 4wd the same tow rating from 15900 to 16800 depending on cab selection.

Fords new 6R140 tranny doesn't have a direct 1:1 drive gear so the lower gear axle ratios for 16k lb isn't needed especially with the big hp/torque number the 6.7 puts out. The 3.31 gears and the 6 speed tranny have similar rpm/speeds to the older 5R110w tranny and 3.9x to 4.x gears

You will have to pay attention to the F350 SRW GVWR and RAWR packages as they vary a bunch so payloads depends on package selections.
Over a dozen GVWRs from 10000 lbs up to 11500 lbs and three RAWR packages from 6290 lbs up to 7000 lbs.

Choose carefully and enjoy.



.

[wandering1]

Originally Posted by D Lindy

Look up the specs on the truck and see what it shows as towing capacity and GVW.

X2. Get the facts.