• Feb 18th 2009 at 12:29PM
  • 30
When Ford debuted its 6F transmission back in late 2005, we were told it could handle up to 300 horsepower and 280 lb-ft of torque. That transmission debuted with the automaker's 3.5L V6 and both are now widely used together in a number of Ford, Lincoln and Mercury products. Times have changed, however, and Ford has introduced a new version of its 3.5L V6 with twin turbochargers and direct injection. Called the 3.5L EcoBoost, this engine makes more power than the original 6F transmission, now called the 6F-50, can handle. Enter the 6F-55, a new version of the 6F-50 with beefed up internals to handle the 3.5L EcoBoost's 355-365 hp and 350 lb-ft of torque. One example is the new ring gear on the 6F-55 (shown at right), which is 41.5mm thick compared to 31.5 mm on the 6F-50.

The 6F-55 will be used initially in versions of the Ford Flex, Lincoln MKS and MKT that feature the 3.5L EcoBoost V6. It will also be the only transmission available for the new 2010 Ford Taurus SHO that features the most powerful version of Ford's EcoBoost V6 (sorry SHO fans, no standard transmission will be offered). Each application will also feature SelectShift for manual operating the tranny with either the console-mounted shifter or paddle shifters on the steering wheel. We'll have to wait for our first turn behind the wheel of an EcoBoost-equipped Ford product to judge just how well the new 6F-55 handles all that extra power, but based on the rather significant list of internal changes detailed in the press release after the jump, the new tranny appears more than capable of handling our heavy left foot.

[Source: Ford]



DEARBORN, Mich., Feb. 18, 2009 – Ford's 3.5-liter EcoBoost V-6 engine debuts this spring with the perfect running mate for maximum performance and fuel efficiency – a six-speed SelectShift automatic transmission that's specifically designed for the higher torque demands of the all-new twin-turbocharged, direct injection engine.

Developed from the successful 6F-50 transmission, the 6F-55 is dedicated solely to the 3.5-liter EcoBoost engine and incorporates a number of component and calibration upgrades that help guarantee every drop of torque produced by the turbocharged V-6 is seamlessly transmitted, giving customers that V-8-like performance they love, as well as the fuel economy they demand.

"Adapting the 6F architecture to the EcoBoost engine demanded a close look at every component, piece of hardware, and calibration measure to ensure that this transmission could answer the needs of a higher output engine; help, not hinder, fuel economy; and meet Ford's strict durability standards," said Barb Samardzich, vice president, Global Powertrain Engineering.

The engine/transmission combination is already proving its muster. The 2010 Lincoln MKS, the first Ford Motor Company vehicle to offer the 3.5-liter EcoBoost engine and 6F-55 transmission package, will deliver an impressive 355 horsepower and a responsive 350 ft.-lbs. of torque, along with achieving 25 mpg on the highway.

That's more power and better highway fuel economy than the V-8 engine found in the 2009 Lexus GS460 (24 mpg) or the 2009 Inifiniti M45 (21 mpg). The recently announced return of the 2010 Ford Taurus SHO also will sport the EcoBoost V-6 and the six-speed SelectShift transmission, delivering an estimated 365 horsepower at 5,500 rpm and 350 ft.-lbs. of torque at 3,500 rpm, while maintaining fuel economy ratings on par with a V-6 engine.

Other 2010 products set to offer this powertrain combination include the Ford Flex and Lincoln MKT.

High Torque Edits
The 3.5-liter EcoBoost engine strategically uses two small turbochargers, which are quick to respond to throttle inputs, spooling up instantly for torque output that's impressive – peaking earlier in the rev range than a comparable, normally aspirated engine. The turbo system does, however, run at higher temperatures.

In order to handle the elevated operating temperatures associated with a turbocharged engine and carry the higher torque produced by the 3.5-liter EcoBoost V-6, the 6F-55 incorporates a blend of hardware, material and calibration upgrades.

The transmission features, for example, wider, thicker transfer and final drive gears, improved input and output carriers, and a new differential case to carry the higher energy produced by the engine and deliver the performance customers expect when they accelerate. The ring gear on the 6F-55, for instance, is a beefier 41.5 mm versus 31.5 mm on the 6F-50.

Final drive ratios have been adjusted and matched to gear ratios to provide optimum performance and fuel economy. Clutches also have been upgraded with high-energy friction materials that can handle higher loads and shift energies over the long term. In addition, clutch piston material upgrades can withstand higher operating temperatures. This, along with thicker thrust washers, and an improved heat treatment on the turbine shaft help handle the higher engine torque.

"We had to bulk up and strengthen all of the transmission's core parts for higher duty cycles," said David Capoccia, transmission system manager, Ford Powertrain Operations. "The thicker gears, the improved carriers, upgraded clutches are all part of a set of hardware actions that translate to superior performance and durability for the customer."

The 6F-55's torque converter was also tweaked to improve drivability and create a more connected feel for customers. The converter even has its own exclusive efficiency curve and design for increased strength and durability, bolstered by four lugs welded on the cover in comparison to three on the 6F-50.

A second roll restrictor boss, which limits powertrain movement during acceleration, was also added to the Lincoln MKS and MKT EcoBoost transmission packages for superior noise, vibration and harshness (NVH) and a smooth, seamless acceleration experience.

Fuel Economy Factors
The 6F-55 may be bigger and stronger, but it is not less efficient, according to Capoccia. Several of the transmission upgrades actually help improve fuel efficiency. They include:

* Friction material grooves, which break up the fluid flow between the friction and separator plates and help pump fluid through the plates, have been optimized to reduce overall clutch drag losses.
* Moving from a six to a nine wave CBLR (Clutch Brake Low Reverse) spring – which aids in mechanically separating the clutch plates – provides a flow path for the fluid that reduces overall clutch drag losses.
* Calibration measures, such as reducing the modulated slip from 40 rpm to 20 rpm allows less fuel to be burned to deliver the same torque to the wheels; and locking up the torque converter in lower gears to expand the operating range and provide optimum fuel efficiency.
* Increasing the start-to-open temperature of the bypass valve by 15 degrees, which allows the transmission to run at higher, more efficient temperatures and save fuel.

A High-Volume Commitment
The addition of the 6F-55 builds on the reputation of Ford's 6F transmission architecture.
And like the 6F-50, the 6F-55 offers customers all the benefits associated with an advanced six-speed gearbox, including superior shift quality, improved acceleration, a more refined driving experience and improved fuel economy. In addition, the SelectShift feature allows the customer to choose gears for a more spirited drive.

"The 6F-55 has all the same features that customers have told us they desire from the 6F-50 transmission, and that includes fluid-fill for life and flat tow capability," adds Bryce Bollwahn, a systems supervisor at Ford's Automatic Transmission New Product Center.

Going forward, advanced six-speed transmissions, along with EcoBoost engine technology, will continue to dominate Ford's sustainability strategy. By the end of 2012, nearly 100 percent of Ford's North American transmissions will be advanced six-speed gearboxes. By 2013, more than 90 percent of Ford's North American vehicle lineup will offer EcoBoost technology.

The 6F-55 is produced at Ford's Van Dyke Transmission Plant in Sterling Heights, Mich., which also produces the 6F-50 and 6F-35. The Van Dyke plant is one of three Ford six-speed transmission Centers of Excellence.

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    • 1 Second Ago
      • 6 Years Ago
      The only reason the SHO came with the manual for the first 4 years was because Ford didn't have an auto tranny that could handle the power.
        • 6 Years Ago
        Clutch is different than transmission. They undersized the CLUTCH - the trans held up to the power fine.
      • 6 Years Ago
      I am not an engineer, but...

      I understand that you can over-design and over-build for anything, and that trying to chase the future is a risky and costly proposition, but it seems odd that the original 6F-50 design was so close to the line at 300hp/280lbft and forced them to re-engineer (what actually looks like just re-tooling) a 6F-55 for 365hp/250lbft.

      I'm thinking whatever costs they saved in the first rev by designing for the future were a net loss once they realized they had to redesign (and re-test, re-tool, etc.). Worse, it almost looks like they'll have to do the same thing again when they need more hp/lbft.

      I'm not harping on the achievement, but the tactical design planning looks short sighted.
        • 6 Years Ago
        It seems that if this were a GM transmission, it would be the 6t"80".
        GM had the 6t70 & 6t75 variants, and Ford's 6F50 is roughly equivalent to GM's 6t70.

        Ford 3.7 V6 is probably the biggest engine to pair with the 6F50.
      • 6 Years Ago
      Awesome 6-speed slushbox!

      Oh wait... most of the competitors use 7 or 8-speed autos or even better dual clutch transmissions.
      Way to go Ford.
        • 6 Years Ago
        Please help control the Troll population. Have your troll spayed or neutered.
        • 6 Years Ago
        MOST competitors??? You mean like $50K Lexus and $70 BMW? Go jump.
        • 6 Years Ago
        Anything above 6-speeds in anything but a peaky, high-revving 4 cylinder is really a pure marketing gimmick. With the fat torque curve the EcoBoost is putting out, you don't NEED more than 6 well spaced ratios.

        Unless you program the transmission to shift at F1 sequential speeds, going through 3 gears just to get to 60 mph will actually slow you down.
        • 6 Years Ago
        Epic fail...

        Since when did your beloved Avalon get a seven speed auto?
        • 6 Years Ago
        It is a good 6 speed auto, 2nd gear is nearly identical to reverse.
        2nd: 2.875, R: 2.882
        Chrysler's 62TE is inferior to the GM-Ford, razz on that one.

        Honda's 6 speed autos are great, wait, what Honda/Acura don't have any...

        If Ford had a 7 or 8 speed auto, then they wouldn't need to offer a significantly shorter axle ratio (14% WOW) in the 'SHO performance package'
        • 6 Years Ago
        In their volume cars? Where?
      • 6 Years Ago
      So you can either choose to manually shift on the steering wheel or on the floor?

      that's good cause if I were to buy one of these I think I would opt for the floor... I'm not too big of a fan of paddle shifters... but that's just me
      • 6 Years Ago
      Wow...you get that trans plus the ecoboost engine, plus AWD all for $700??

      • 6 Years Ago
      And the lack of a manual tranny is the biggest slap in the face to real SHO fans. C'mon, the SHO was manual ONLY for its first four years.

      I'll be curious how responsive the shifts are to the "manual" input. I'm sure it will be a snoozefest waiting for your requested gear to engage.

      Or if it will hang on to a gear while it's banging off the rev limiter...or more likely force you into the next gear.
        • 6 Years Ago
        It should do both:
        If the traction control is on, the transmission should auto-upshift at the redline
        If the traction control is off, the transmission should hit the rev limiter in low gears (1 & 2 with the 2.77 axle ratio, 1,2,3 with the 3.16 axle ratio-SHO performance package) and use throttle by wire to hold the engine speed steady at 6200-6300 -ish.

      • 6 Years Ago
      "...the new tranny appears more than capable of handling our heavy left foot. "

      I've heard of left foot braking, but this is news! Is this a new Heel-Toe driving technique?
        • 6 Years Ago
        Haha I was just about this point out the same thing! I really don't get you...
        • 6 Years Ago
        It's for lefties lol
      • 6 Years Ago
      If they aren't talking manual shift, I am un-interested.

      However, if you aren't talking about limited slip differential, it is going to be a torque steer monster.

      Thanks... but no thanks.
        • 6 Years Ago
        I like manual, but, honestly, it's really sort of going the way of the Do Do bird. As sports/sporty type cars become better for everyday use and expand their customer base, manuals make less sense. Automatics and the transmissions that allow you a choice just make more sense.

        Other than the clutch peddle, what is really that different? What are you really missing?

        If you're a city dweller or a commuter, a manual is a bit of a hassle in heavy traffic. They were fine when sports cars only came out on Sundays, but, if you can drive your Lambo everyday, do you really want to be shifting on the 405 at 835am?

        Methinks a lot of the people who swear allegiance to the traditional set up also have Betamax in their homes because, "the quality is SO much better than VHS."

        There's a whole new world out there folks.
        • 6 Years Ago
        It's AWD. The push of the rear wheels mitigates the torque steer at the front wheels somewhat, if they are engaged.

        Go drive a Mazdaspeed6 or Volvo S60R. Both have similar power to this and have FWD with part-time auto-engaging AWD. They probably have almost the same drivetrain, given Ford made all of them.

        They don't really drive like a full-time AWD car, but they're quite acceptable.
        • 6 Years Ago
        I'm pretty sure Boxer is being pretty neutral when he says "They can have different options. And Manual transmissions have their advantages." That's not saying Ford hasn't done their research or that manual transmissions are going to make a wonderful and glorious mainstream comeback. What I take from it is that when Ford expects to woo enthusiasts to its new high performance model, having the option of a manual transmission would strengthen this message not hinder it. I think its funny that for one post on manual transmission support there are a half-dozen slushboxers that get their undies in a knot, then say the minority drivers who are too 'vocal' about their passion for using a clutch just move on and don't post. Kind of hypocritical, isn't it?
        • 6 Years Ago
        And preferring to shift one's own gears, with a mechanical clutch engagement, rather than a fluid torque converter (viscous connections work nicely to allow slip, they don't work as well when you want a direct connection)

        That is not "beta-max" vs. VHS, or BluRay Vs. HDDVD, or anything else.

        Not every car HAS to be universal. They can have different options. And Manual transmissions have their advantages.

        I won't own a car with ANY amount of sporting pretense, even an ounce, that has an automatic transmission. I shift for myself, thanks. and it is more than pushing an electrical switch making a suggestion for the transmission to shift itself. If I wanted that, I would go for DSG/PDK or other dual-clutch gearboxes, which at least still have clutches, not a torque converter and hydraulic pressure shifting, which is slow to respond.
        • 6 Years Ago
        The SHO performance package will probably torque steer.
        The axle ratio is substantially shorter (3.16 vs 2.77, 14%, only slightly offset by the 1% difference in tire size)
        and it has skinnier tires 245/45 20 vs 255/45 19
        This is iteration 4 Haldex, it engages quicker than the turbos can spin up.

        Where is the rear 'eLSD'?
        • 6 Years Ago
        If you're uninterested, why do you keep taking the time to comment on how uninterested you are every time one of these stories pops up? We get it. You want a manual transmission. So do an extremely vocal but relatively insignificant number of other people and of those, only a portion would actually put their money where their mouth is and buy a manual SHO. The manual's not going to happen so let it go.
        • 6 Years Ago
        @Boxer -

        For a guy who hasn't even seen the car in person, much less driven it, you sure got it all down. Golly, you must be WAAAAYY smarter than the engineering staff at Ford. Seein' as how you know all about haldex, and shaft length, and torque steer, and all that stuff THAT YOU'VE READ UP ON IN MAGAZINES. I'll be those guys at Ford didn't think about ANY of that.
        • 6 Years Ago


        Oh, you have a Legacy? We weren't sure. Make sure you post in every single thread about your car. You should be proud of it. Please, don't be shy.
      • 6 Years Ago
      I look at the power, torque, and fuel economy again, and I simply marvel at them all. Well done Ford!
      • 6 Years Ago
      I honestly think I'm going to move to Australia. I'll have to get used to driving a RHD car, but I think I can do that. Having a manual trans option in most cars with a big V8 sounds good to me! (Also getting out of the snow would be nice) I hate that all car companies think that no Americans want a manual transmission. The sad thing is the general American public probably doesn't :(
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