The high-speed off-roader uses a trick transfer case with clutch and and mechanical engagement.
What’s the difference between four-wheel drive and all-wheel drive? That’s a question many people have asked over the years, because they aren’t the same. To keep things simple, all-wheel drive systems are generally clutch-based, whereas four-wheel drive systems utilize a mechanical connection where components are locked. In real-world applications, all-wheel drive is better suited functioning all the time, on both loose and high-traction surfaces. Four-wheel drive systems are far more robust for off-roading, and because they use locked mechanical connections, are not suitable for full-time engagement. Just ask any pickup truck owner about replacing expensive front hubs because they didn’t unlock when four-wheel drive was disengaged.
We offer this description because Ford’s new F-150 Raptor has both designs. It uses a Terrain Management System with a dual-mode transfer case, featuring clutch-based all-wheel drive functionality and electronic lockers for proper mechanical connections when off-roading.
“Raptor’s transfer case provides the best of both worlds, with the natural benefits from all-wheel drive, such as increased traction in rain and snow, as well as extreme off-road capability that comes with a mechanically locked system,” said Tony Greco, Ford F-150 Raptor program manager, in a press release.
All functions are controlled through the Raptor’s Terrain Management System. For every day commuting, Raptor drivers can use the 4x4 auto setting. This uses the clutch-based feature of the transfer case to transmit power to the front axles, and can be fine-tuned by selecting weather mode for slippery conditions, or sport mode, which sends more power to the rear for spirited driving.
When the road ends, drivers can select mud/sand mode to automatically engage 4x4 high using a traditional, mechanical engagement. Rock crawl mode engages 4x4 low for low-speed maneuvering with an additional gear reduction ratio. Drivers can also manually override the settings to fine-tune the Raptor’s performance for the specific situation, be it sailing down trails at speed or navigating a crowded mall parking lot. We've had the opportunity to experience the Raptor's capabilities first hand, and we'll give credit where credit is due. Whether launching over dunes or towing a Mercedes wagon, the Raptor seems eager to please.
Combined with a 450-horsepower EcoBoost V6 and 10-speed automatic transmission, Ford is betting heavily on the new Raptor to be an even bigger success than the previous generation. That said, Ford F-Series sales declined slightly in April, though dealers report strong demand for the revamped off-roader.
Gallery: 2017 Ford F-150 Raptor: First Drive
RAPTOR'S CUTTING-EDGE TERRAIN MANAGEMENT SYSTEM ENABLED BY CUTTING-EDGE AWD/4WD TRANSFER CASE
- All-new 2017 F-150 Raptor features a cutting-edge transfer case that merges all-wheel-drive and four-wheel-drive capabilities for handling virtually any situation – including sport, weather, four-high desert and four-low locked off-road driving
- Controlled automatically via all-new Terrain Management System™, or manually by the 4x4 switch, innovative transfer case offers an electronically controlled clutch-based, on-demand system that delivers outstanding performance – for confidence whether on-road or off
- Specially designed transfer case employs an electronic shift-on-the-fly system featuring mechanical locks to tackle all types of terrain for serious off-road performance – including nearly 2,500 miles of off-road competition testing
DEARBORN, Mich., May 4, 2017 – When the all-new F-150 Raptor hit showrooms last fall, few could foresee the extent of the innovations beyond its high-output engine and new skin. Along with all the power and agility gains comes the most advanced drive mode system in its class* – a cutting-edge Terrain Management System™. It is enabled by an all-new dual-mode transfer case that incorporates both all-wheel-drive and four-wheel-drive systems and electronic lockers to deliver the ultimate multi-terrain experience.
To give Raptor drivers more performance and capability both on-road and off, Ford Performance engineers developed this all-new transfer case to manage the distribution of power between front and rear wheels. Key to that is clutch-based, on-demand all-wheel-drive capability for everyday driving, including all-weather mode, while also providing a mechanically locked, durable four-wheel-drive system for confidence in severe off-road driving environments.
When combined with the non-sequential 10-speed transmission and high-output EcoBoost® engine, Raptor can deliver its 450 horsepower and 510 lb.-ft. of torque more efficiently for the ultimate driving experience – whether you’re on the road or way, way off.
“Raptor’s transfer case provides the best of both worlds, with the natural benefits from all-wheel drive, such as increased traction in rain and snow, as well as extreme off-road capability that comes with a mechanically locked system,” says Tony Greco, Ford F-150 Raptor program manager.
Typically, four-wheel-drive options for trucks come in two transfer case varieties – on-demand systems that employ a clutch to transfer torque to the front driveline, similar to how all-wheel-drive setups work, or electronic shift-on-the-fly systems that use mechanical locks to couple the front and rear driveshafts.
Ford engineers sought to enhance the daily driving experience of Raptor while preserving its ultimate off-road performance. With the clutch-based feature of the transfer case, drivers can travel on-road using the 4x4 auto setting, which delivers the benefit of four-wheel drive without the repercussions of component damage or driveline binding – something that can occur when drivers try to use mechanically locked systems on high-traction surfaces like pavement.
Ford fine-tuned the calibration of 4x4 auto depending on road surface conditions, so the transfer case can vary the clutch torque to suit the environment. For example, when the driver selects weather mode via the Terrain Management System, it’s tuned for slippery surfaces, while sport mode is tuned to feature more of a rear bias that can provide a fun driving experience, including better acceleration and on-road performance.
When Raptor is operating off-road, its electronic shift-on-the-fly system is still available in the form of 4x4 high and 4x4 low – enabling drivers to navigate harsh terrain with confidence and added robustness. In mud/sand mode and Baja mode, the transfer case shifts into 4x4 high, making it optimal for tackling trails and loose or soft ground – as well as engaging in high-speed desert runs. In rock crawl mode, the transfer case employs 4x4 low, enabling intense off-road driving and rock climbing at low speeds, while using an additional gear reduction ratio to provide enhanced capability with improved powertrain response.
In all cases that involve severe environments or conditions, the transfer case delivers flexibility for elite performance. While the Terrain Management System is designed with default 4x4 settings, drivers can manually override the settings to further fine-tune the system for a different experience.
The system was performance-tested in nearly 2,500 miles of competition testing in the 2016 Best in the Desert series, completing the 850-mile SCORE Baja 1000 to conclude the season. In the end, Greg Foutz Motorsports team members drove the truck another 400 miles back to their headquarters in Arizona.
*Class is full-size pickups under 8,500 pounds. GVWR based on Ford segmentation.