2015 6.7 mpg?
#22
Now this may be a stupid question so go ahead let me have it! Are all SDs equipped with a dial to shift from 2-4wd shift on the fly? Noticed shift on the fly was an option on 14 models in the build your own website not on the 15 though. Reason I ask is mine clunks a bit when shifting and yes I do it at low speeds.
#23
Senior Member
I'd think those 4.30 gears will kill you. I'm running a 15 F350 DRW with 3.73's pulling a 30 ft horse trailer I get around 13.
#24
Now this may be a stupid question so go ahead let me have it! Are all SDs equipped with a dial to shift from 2-4wd shift on the fly? Noticed shift on the fly was an option on 14 models in the build your own website not on the 15 though. Reason I ask is mine clunks a bit when shifting and yes I do it at low speeds.
#25
Junior Member
I agree that 3.73 would be preferable for mpg but these 4.30 gears are showing the same mileage I had with my 2010 F250. I was wanting 3.73 but this truck came with high capacity towing which included 4.30 gears. In town driving has been around 14 mpg. I just towed my toyhauler 100 miles into a stiff headwind on Thursday and got right at 10 mpg. Winds should be in my favor returning home tomorrow. The engine rpms are only about 300 more than a 6.4L with 3.55 gears. So far as I can see, the 4.3 gears are "affordable" considering that this truck goes to 6th gear readily and stays there without lugging the 6.7L. The 6.4L with the 5 speed would readily drop to 4th gear with most any load while cruising. Also, the turbo gauge stayed at 1/2 way point during towing, This 6.7L stays below 1/4 and closer to 0 on the turbo gauge.
#27
Junior Member
I guess that would fall under "Ford's better idea". In my opinion, 3.73 gears in an F250 6.7L would probably mean increased towing capacity that Ford would not want on that SRW truck. Down here in south Louisiana I am seeing more than a few guys pulling fifth wheel, 3 axle rvs weighing 18k to 20k pounds, using SRW F350s and some F250s. Obviously these trucks can physically tow heavy rigs well past rating capacity. I went to an F350 DRW to improve handling and stability. At times Thursday I was towing in strong crosswinds and didn't feel it compared to previous towing experiences with my old F250 SRW.
#28
Senior Member/Vietnam Vet
I just ordered a 2015 F-350 PSD SRW and shift on the fly is a $185 option. Standard gearing on the SRW is 3.31. I added the plow prep package to get the 3.55 gearing. I didn't try a dually build, but suspect higher gearing because they are built for a higher payload.
#30
Junior Member
There are a lot of duallys sitting in new inventories at the dealerships with 4.30 gears. That's how I found mine. You just have to search the Ford extended inventory and change zip codes to move around to different areas.