• Jan 2, 2008
Rather than wait for the 2009 model year to roll around, Ford has decided to introduce two new fuel saving changes to the 2008.5 Super Duty that should improve fuel economy for the big trucks by about 1.5 mpg. That may not sound like much, but for vehicles that barely break the double-digit barrier in mpg, it's a big improvement. The changes include reducing the rear axle ratio on certain F-250 and F-350 models and extending their underbody chin spoilers by 3.93 inches. If you're a truck person, you're no doubt wondering how Ford will maintain the maximum tow rating for these trucks while reducing their rear axle ratios. With big trucks, a higher rear axle ratio means more towing capacity, while a lower rear axle ratio provides better fuel economy. In this case, Ford says that these Super Duty trucks will still be able to tow the same amount of weight as before, though our friends at Pickuptruck.com suspect that 0 to 60 performance and acceleration in general, especially while towing, will drop. Click here to view the specific changes for each iteration of the Super Duty that's affected.

[Source: Pickuptruck.com]


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  • 19 Comments
      • 7 Years Ago
      "Lowering chin spoiler", Hmmm...... Wonder how that will work on the job sight eh? I see 'em all busted up now because they stick down to low and get hit with everything. Great idea on a vehicle that routinely needs good ground clearence. As to the axle ratio redux- sometimes when you need to "hump" a little with a load, you punch it expecting good results,(power). If it ain't there, you just keep your foot in it. So how much are we saving now par'dner?
        • 7 Years Ago
        after-market adjustments do not count towards CAFE, so... ripping that spoiler off, or Ford selling one at a discount gets em by.

        As for the axle rating, again towards CAFE. in the scheme of things, I'm guessing a relatively cheap tweak to the ECU will take care of any issues there after its sold if it is an issue.

        As mentioned 1.5mpg doesnt sound like much but you are talking 10% in two easy moves.

        the hard part will be the computer tests to find little ways to streamline the body and get another 5 or 10%.
        • 7 Years Ago
        geo.stewart: These trucks are too big to count in CAFE calculations.
      • 7 Years Ago
      Token effort at best, but this sure is a sign of the times.
      • 7 Years Ago
      Perhaps an effort to stave off governmental meddling in business affairs?
      • 7 Years Ago
      The problem is the 3 speed auto + overdrive, let the stick guys keep on, keeping on.
      Where is the ZF 6hp34? If you ask ZF, they will build it. Ford can get a group buy with BMW & the VW group.
      If Ford gets this transmission, no axle ratio change would be needed.
      Mileage could be 'found' through a more aggressive torque converter lockup strategy. Even lockup in 1st gear with tow/haul mode.
      A side benefit would be a markedly shorter reverse gear ratio, though it would still be taller than the Duramax/Allison & Cummins/,
      Though the turbodiesel would have to be derated some, not as much as the 325hp/600ft-lbs in manual transmission & 4.88 axle automatics. Say 340hp & 625ft-lbs.
      If they really wanted mileage, Ford could switch the axles from 75w-140 to 75w-90 oil.
      Add capacity to prevent overheating, or add fins to the cover, or add a system to circulate a coolant through the differential to cool the oil as needed. (keep 75w-90 under 175C)
      http://www.mobil.com/USA-English/Lubes/PDS/GLXXENPVLMOMobil1_Synthetic_Gear_Lubricant_LS_75W-90.asp
      http://www.mobil.com/USA-English/Lubes/PDS/GLXXENPVLMoMobil1_Synthetic_Gear_Lubricant_LS_75W-140.asp
      or use half 75w-90 and half 75w-140.

      PTO for automatics? maybe it is time for an electric PTO. Dual alternator is/was an option?
        • 7 Years Ago
        The TorqShift is a 3 speed automatic + an overdrive.
        First is first of the 3 speed auto.
        2nd is still first with overdrive on.
        3rd is 2nd of the 3 speed auto, with out overdrive.
        4th is 3rd (1:1) of the 3 speed auto, still without overdrive.
        5th is still 3rd, now with overdrive.

        http://atsg.biz/articles/html/Ford%205R110W%20Torqshift/Ford%205R110W%20Torqshift.htm
        http://www.intellidog.com/dieselmann/60psd.htm
        http://www.pickuptruck.com/html/2003/ford/superduty/first_drive/page2.html
        The transmission strategy worked with the high revving 6.0, but doesn't work with the conventional revving 6.4.

        The only people that like the tall reverse gear are snow plow drivers, everyone else like having a very short reverse gear, say if you are backing up a 10,000 lb trailer uphill.
        • 7 Years Ago
        What 3speed +OD are you referring to? I was under the (rather solid) impression that the Powerstroke, which is mostly what we're talking about here, given its 75+% take rate, was backed with the 5 speed powershift trans. Higher rear axle options would be fine for many users that do more carrying than pulling. If they're really getting a 1.5mpg improvement, thats awesome- that amounts to 10-15%. Thats HUGE. Deeper axles will still be available. As for ground clearance- the write-up says "certain" models, so perhaps it's intended for 2wd trucks.
      • 7 Years Ago
      My brother-in law bought a 2008 F350 and on a recent trip hauling 3 adults and a kid to NC he told me he looked down at the instant fuel economy and it was showing 8.5mpg going down the highway! I'm sure he would gladly take the taller gears and additional 1.5mpg, as he drives ~ 60,000 miles for year for his construction business.
        • 7 Years Ago
        Thats horrible- I've been running an 08 6.4 powerstroke 4wd CC DRW in testing (8000# vehicle weight) and I'm seeing 12-13mpg. If his truck is brand new, it will improve some. The fuel econ will be that low if the truck is running a re-gen, where raw fuel is dumped into the exhaust to burn off captured particulates.
      • 7 Years Ago
      I wonder what generated interest in fuel economy. [/sarcasm]
        • 7 Years Ago
        Is there a law that says pickups must have the aerodynamics of a brick?
      • 7 Years Ago
      Ohhh booo hooo. The only thing these people tow is their wives and their multiple chins.
      • 7 Years Ago
      You guys had it backwards on the gear ratios. A lower ratio gives more torque to the wheels (numerically higher, but a lower ratio). While a higher ratio gives less torque, but you run fewer RPM on the HWY.

      For instance, 3.73:1 gears are a higher ratio than 4.10:1 gears.

      But as other said, trucks have so much power these days the gear change should not change much.
      • 7 Years Ago
      When I first saw this I tought it was a mid engine pickup.
      • 7 Years Ago
      Oh, please. Modern trucks - especially with modern, 6 speed transmissions - generally have more than enough power. I actually had a '99 F350 with the V10 - by today's standards, "laughably underpowered," and the first time I towed with it after selling my '93 (only 10k lbs) I was overall happy with the power but slightly disappointed. Then I realized that, for some stupid reason, I'd dropped the transmission into 2nd gear for the launch instead of drive.

      My older truck was diesel with a manual transmission that topped out at around 13mph in 1st gear. Even in the "pre-turbo" diesel days, I could uphill start more weight than I could comfortably tow.

      There's no real reason to keep penalizing highway mileage for the majority of people who don't need 4.33:1 gears but buy them anyway because they're "for towing." Folks who actually need that kind of pull can easily get it, after all - and they're almost certainly not cutting down the 450-650 line (which, in today's world, are often cheaper as well as being more powerful than the more-blinged-out 250/350s).

      Just MHO of course. And for everyone who "absolutely needs" every last piece of performance from their truck, all day every day... how on earth did they ever survive 10 years ago, before everyone and their dog was driving a 650 lb ft diesel? Amazing...
        • 7 Years Ago
        Arent those 7.3s great! Although 13 mph is generous, more like 1.3 mph in first (one day I will be rear ended taking off from a light...) I still have mine, and beat on it as a workhorse at least every other day, tows anything I strap to the back of it with no complaint, I dont even think it slows it down. The most complicated piece of electrics on it is the radio. If im not loaded with 3.75s in the rear I can get an honest 21mpg. Towing a VW across NY (at 60 Ill admit) I got 20! I bought a new one thinking that surely in 15 years things have improved. They did, they ride nicer, and they stop a whole lot better, but I cant park the damn thing, it barely fits in the garage, and 16mpg, hmmm I rather like the old one more every day, but maybe I can keep the brakes...
        • 7 Years Ago
        No kidding. To hear some people tell it it's a black mark if the truck and 8,000lb trailer has to kick out of OD to keep speed on a grade.
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