Axle ratios?
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Junior User
Joined: Jan 2002
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From: Southwest lower MI
Axle ratios?
I'm considering the 3.31 non limited slip axles on a F350 with 6.7 truck I'm going to order. My thoughts are with the tremendous torque this engine has, higher gearing may be fine for those times when I'm not dragging a trailer around. And when I am, all my trailers are < 14K# and I can keep it out of 6th. If I get into a hairy situation there is always the 4L option which I've only used a handful of times on the the two V10's that I've had. Am I nuts in my reasoning?
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I'm considering the 3.31 non limited slip axles on a F350 with 6.7 truck I'm going to order. My thoughts are with the tremendous torque this engine has, higher gearing may be fine for those times when I'm not dragging a trailer around. And when I am, all my trailers are < 14K# and I can keep it out of 6th. If I get into a hairy situation there is always the 4L option which I've only used a handful of times on the the two V10's that I've had. Am I nuts in my reasoning?
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Junior User
Joined: Jan 2002
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From: Southwest lower MI
The only thing I'd think about is what kind of tires you plan on getting? My truck (same as yours) has the 20" tires. Apparently with the 3.55 rear end that my truck will have, the axle ratio will really be close to 3.31. I think that you may not be able to get a 3.31 with 20" tires but I forget. Anyone?
Junior User
Joined: Jan 2015
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From: Tulsa, OK
Ok, I have a somewhat similar question, but maybe not. I'm looking to buy a Lariat F-250 6.2L in 2WD. I want the E-Locker but I don't know anything about gears. The only available gears with my setup and E-Locker are the 3.73 and 4.30. What is the difference and how do I decide which is right? I plan on hauling a 7x16' tandem axle box trailer that weighs about 5,000lbs on average.
(I know the F250 is overkill for this weight but I put on about 35-40k miles per year so I wanted an a vehicle made specifically for towing, not the F-150.)
(I know the F250 is overkill for this weight but I put on about 35-40k miles per year so I wanted an a vehicle made specifically for towing, not the F-150.)
Cargo Master
Joined: Dec 2003
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From: Central MO
Ok, I have a somewhat similar question, but maybe not. I'm looking to buy a Lariat F-250 6.2L in 2WD. I want the E-Locker but I don't know anything about gears. The only available gears with my setup and E-Locker are the 3.73 and 4.30. What is the difference and how do I decide which is right? I plan on hauling a 7x16' tandem axle box trailer that weighs about 5,000lbs on average.
(I know the F250 is overkill for this weight but I put on about 35-40k miles per year so I wanted an a vehicle made specifically for towing, not the F-150.)
(I know the F250 is overkill for this weight but I put on about 35-40k miles per year so I wanted an a vehicle made specifically for towing, not the F-150.)
Junior User
Joined: Jan 2015
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From: Tulsa, OK
A majority of my driving is on the interstate, turnpike or main highways. (I'd say 85%highway/15%town.) 65-85mph even with a 5,000lb trailer. My 5.4L 4x4 F-150 gets about 9mpg. What is a good guess for a 6.2 with 3.73's in the same conditions?
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Cargo Master
Joined: Dec 2003
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From: Central MO
I'm just making a SWAG here, but I would guess about 9-10 MPG. The Super Duty is heavier, but the 6.2L should be a tad more efficient pulling the load.
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Junior User
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From: Southwest lower MI
I have the 6.8 on a F250 and the reason I'm going to diesel is for the low end torque. My truck will pull the 5-14K in the neighborhood of 2500 rpm at 55mph. And if I stomp on the pedal and get into the power band of 3.5-4.5K it moves pretty well. But I think that the 4.3 over the 3.73 would have been a better option on this truck for towing. I drove a 6.2 last Friday at the dealer and thought that it drove just like my 6.8. I'd like a little better response from a dead stop or pulling up a hill and I think that the 4.3 would do that?
Cargo Master
Joined: Dec 2003
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From: Central MO
I have the 6.8 on a F250 and the reason I'm going to diesel is for the low end torque. My truck will pull the 5-14K in the neighborhood of 2500 rpm at 55mph. And if I stomp on the pedal and get into the power band of 3.5-4.5K it moves pretty well. But I think that the 4.3 over the 3.73 would have been a better option on this truck for towing. I drove a 6.2 last Friday at the dealer and thought that it drove just like my 6.8. I'd like a little better response from a dead stop or pulling up a hill and I think that the 4.3 would do that?
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Junior User
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From: Southwest lower MI
As for fuel mileage estimates keep in mind that the there is not a lot of difference in the square footage of the fronts of both the trucks. And the amount of energy necessary to push that through the air is not a linear relationship to speed. I'd consider myself lucky to drive at 85 with my 6.8 and expect to see anything over 11 empty.
Cargo Master
Joined: Jan 2015
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From: Boise
Ok, I have a somewhat similar question, but maybe not. I'm looking to buy a Lariat F-250 6.2L in 2WD. I want the E-Locker but I don't know anything about gears. The only available gears with my setup and E-Locker are the 3.73 and 4.30. What is the difference and how do I decide which is right? I plan on hauling a 7x16' tandem axle box trailer that weighs about 5,000lbs on average.
(I know the F250 is overkill for this weight but I put on about 35-40k miles per year so I wanted an a vehicle made specifically for towing, not the F-150.)
(I know the F250 is overkill for this weight but I put on about 35-40k miles per year so I wanted an a vehicle made specifically for towing, not the F-150.)
Logistics Pro
Joined: Jan 2013
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I'm considering the 3.31 non limited slip axles on a F350 with 6.7 truck I'm going to order. My thoughts are with the tremendous torque this engine has, higher gearing may be fine for those times when I'm not dragging a trailer around. And when I am, all my trailers are < 14K# and I can keep it out of 6th. If I get into a hairy situation there is always the 4L option which I've only used a handful of times on the the two V10's that I've had. Am I nuts in my reasoning?
You nail that 6.7 from a stop and by the time the tires catch up to the rpm of the engine you will be driving on rims.
My '15 with 3:73 and limited slip is traction challenged on wet streets right after a rain, especially so when we go a couple of months with no rain at all then a sudden downpour floats oil droppings to the surface.
If you want to run a 3:31 its gonna need some kind of traction device??????????????
If I am wrong please say so.
Elder User
Joined: Aug 2016
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As much as I try to feed those data points into my brain it just says the same thing over and over: non sequitur...and will listen to any view that says shoving 800+ lbs of torque thru a set of 3:31 gears and no traction device (limited slip/locker) makes good sense.
You nail that 6.7 from a stop and by the time the tires catch up to the rpm of the engine you will be driving on rims.
My '15 with 3:73 and limited slip is traction challenged on wet streets right after a rain, especially so when we go a couple of months with no rain at all then a sudden downpour floats oil droppings to the surface.
If you want to run a 3:31 its gonna need some kind of traction device??????????????
If I am wrong please say so.
You nail that 6.7 from a stop and by the time the tires catch up to the rpm of the engine you will be driving on rims.
My '15 with 3:73 and limited slip is traction challenged on wet streets right after a rain, especially so when we go a couple of months with no rain at all then a sudden downpour floats oil droppings to the surface.
If you want to run a 3:31 its gonna need some kind of traction device??????????????
If I am wrong please say so.
As far as the 2017's go with the increase in torque and hp they programed the computer to not bring on all that torque and hp until you are in third gear, then it gives it all to you. So that solves the torque twisting power out of the hole.
So the maybe on the locker is what you use it for, off road, mud, snow, yes I would add a locker.
Highway and around town you don't need one.
Now IMHO for the cost, buy the locker. My 250 is ordered with 3.31 with the elocker.