I will be ordering a new truck this week and want to test drive an F-350 with the 6.7 diesel and 3.31 gears to see what kind of mpg's it gets. The problem is I can't find any dealers that have the 3.31 gears in any of their trucks????!!!! Will the 3.31 gears be too low to tow 15,000 lbs as well as the 3.55 gears which are most common on these trucks? I figure the diesel with the 3.31 gears can't be any less powerful than the gas motor with 3.73 gears but what does everyone here think? The other question on the 3.31 gears is does anyone know the mpg difference between the 3.31 and the 3.55 in case I can't find one to test drive I am not too confident in ordering a truck that I haven't' been able to drive and make sure I am happy with the gearing?

 

I have that config, it tows my trailer like it's not there....fully loaded, around 12K lbs....Towing mpgs, at 10.5....Empty mpgs, at 19.


Good luck

 

Great to hear. Did you have to order your truck or find it on the lot? I am hoping with 60% highway driving at 72-78 mph and 40% city usually avg 35 mph the 3.31 gearing will average 18 mpg. If it does I will be buying the diesel. If it doesn't I think I will have to go with gas because I feel that 18 mpg is the magic number at 20,000 miles per year where it makes sense to go diesel with extra cost of fuel, maintenance, and price of motor. Do you think 18 is a realistic number seeing that you have it (and I don't mean babying the truck just to get good mileage, I like to drive normally with a lean towards aggressive driving style on acceleration)

 

18 mpg is realistc...other factors to consider, I live in Florida it's flat, and it's warm so NO winter fuel...As far as the city to hwy mix driving, we are pretty close.

I had ordered a truck with the same specs, but, after 5 or 6 weeks and I didn't get a VIN #, I found the truck I currently have up in Orlando...I bought my truck May 1, 2010....

 

My F350, 3.55's and the 20" wheel package (they are bigger overall diameter than the 18" wheel/tire option) has been getting around 19-21 on the Highway cruising between 65-80. Have not towed yet, but I guess what I'm saying is that the 3.31 doesn't get you THAT much in the MPG field... from my experience.

 

I have the NittoTerra Grapplers 295/70 r18, 1" larger diameter than stock.

 

I have a F250, 3.31 with 18" wheels. Summer I average 17mpg but that's with 80-90 city. When I do a trip with all highway I see 22 to 24. Winter fuel I drop to around 16. Even if it's close on the break even with a gas truck I think you will enjoy having the diesel even if it costs a little more.

 

First, the 6.2 is a great motor, but not in the same ballpark as the 6.7 diesel with 800 lbs of torque.

second question. The difference in gearing will be negligible. I have 3.55 and avg 16-20 mpg and 10.5 towing 13k.

 

Well I just test drove the diesel then gas motors and was I impressed! I love the diesel motor, I did a short loop about 10 miles 50-75 mph and it averaged 18 mpg on the screen which I know you can't believe but I did apples for apples and when I drove the gas motor same loop same mph it got 13 mpg. At current gas/diesel prices doing 22,000 miles per year I figure I will save around $736 on the conservative side a year. The motor cost is $6500 more with the current diesel discount so I see it taking about 8.5 years for a full payback on the motor WORST CASE SCENARIO just on fuel alone. When you figure in resale value, the pleasure of driving the diesel, and me doing more like 25,000 miles a year and the truck averaging more than 18 mpg with the 3.31 gears I am pretty sure I will be ordering myself my first diesel in a pickup truck!!!! Can't wait.

 

You'll pay a premium for the diesel, no way around that.
Engine is more, fuel is more and plenty of expenses in standard maintenance items.
If you need the diesel, well then it's that simple, you need it.

I still smile the same as when I picked it up but don't get your hopes up on MPG, as you said.
I have the 3.31 and lately the only time I see 18.x MPG is empty driving east on the interstate at no faster than 75 MPH.
Sometimes I've seen 19 but it's been awile.
Towing a few thousand lbs of something low profile on my trailer I see in the 14's.
Add something that adds wind resistance like a tractor and I'll see low 12's.
Still better than the all stock 2010 6.4L I've driven that I swear has never reported 10.0 MPG.

The F-350 SRW is a great idea, too.
Had I known how soft the 2011 F-250 model leafs were, I would have bypassed the F-250.
Anyways, when you finally get it, we must have pictures!

 

OP, What state are you in? There is a 350 CC long bed 6.7 3.31 in Georgetown Texas. XLT for 50k. Also, this truck has the manual 4x4 selector instead of electronic shift on the fly (there was a post about this not long ago). The e-locker is on the *** where the shift on the fly would be.

Ohh, looks like you're in Pittsburgh... My hometown! I'll drive it up for ya if you want lol

 

I have the 331 in my 11 350 4x4 and just got back from a 3400 mile hunting trip pulling my 30' 5th wheel with a total combined weight of close to 23,000 lbs.
The driving was about 2500 of trailer pulling and the rest in the back country and 4 wheel quite a bit. I pull my trailer at 65 on the highways.

My total overhaul fuel milage was 10.0. While pulling the trailer my high was 10.7 and I saw a low of little under 7 (that was with a 30-40 milew head wind for 200+ miles). There are very few hills that slow the rig down below the 65 with cruse control set. It just drops gears and goes.

Hope it helps, the truck has pleanty to pull anything with the 331 gears.

 

I have the 3.31 gears in my F-350. I would not buy any other gears for my use of the truck. I've only had 12k on the back of mine, but I had plenty of power for anything I need. The new 6AT has much better gearing for pulling and the 3.31 gears are great.

I drove from Dayton to Indianapolis and back this weekend. Round trip MPG for 240+ miles was 19.91 MPG (hand calced) on winter diesel. My 6.4 tuned couldn't do that if I pushed it.