Four words: Power Fold Third Row

 

Had a Burb, traded it for the Expy. My thoughts were, more passenger room in the Expy, and much more leg room for my girls in the 3rd row. Liked the interior of the Expy better, really like the floor shift as opposed to the steering column shift of the Burb. The powerfold 3rd row is a big plus, no more taking a seat or two out like in the Burb. I also tow a 24' motorcycle trailer, and the Expy tows just fine. I have towed this with Dually's, Powerstroke F250's, Burbs and now the Expy. It is comparable to all. Gas mileage is no better or worse than the burb

 

Thanks for all the input.

I think I would prefer an Expy. I just wish I could find a low mile 2010 closer to me.

The Suburban stands out mainly because its 1 hour away from me and has 3,500 miles. The nearest Expy I have found that I like is about 8 hours away and has 24,00 miles

 

Expedition (2003-present) uses something MUCH, much better than a rear limited-slip differential. It uses traction control. TC can transfer up to 50 percent of the engine’s supplied torque to the drive wheel(s) with the most traction.

The system uses the Expedition’s ABS brakes rather than a clutch pack inside the rear differential (that’s basically all the limited-slip differential is; a open differential with a clutch pack that engages to transfer torque) Take away the clutch pack, and you take away the differentials ability to transfer torque.

Some limited-slip differentials will revert back to an open differential when their clutch packs wear out. Traction control is good for the life of the vehicle.

How traction control works: the ABS brakes clamp down on the slipping (spinning) drive wheel(s) and then release causing resistance, thus forcing the open differential to transfer more torque to the wheel(s) with better traction, allowing the Expedition to continue moving.



Expedition 4x2 gets 2-wheel traction control

Expedition 4x4 gets 4-wheel traction control

Since the system can work at all four drive wheels, the Expedition 4x4 performs like having front and rear limited-slip or locking differentials, it’s that good!

In the right situations, a four-wheel-drive Expedition can keep moving forward even if only one drive wheel has traction, no matter which wheel it is; left front, right front, left rear or right rear.

Off road, the Expedition can keep moving even if two of its drive wheels are completely off the ground (i.e. one front drive wheel is airborne and one rear drive wheel is airborne)

 

GL&W... thanks again for making me smarter! I really appreciate the knowledge you share with us.

 

This is a great post, but previous to this post I was fully aware of how traction control works. Call me "old school" but there are certain situations where I'd rather control my own wheel spin rather than the computer retarding my throttle input and braking for me.
The AdvanceTrac with RSC is a great system for the everyday consumer that is unfamiliar with conventional 4wd systems and it is a wonderful aid.
With that being said, I'm glad Ford utilizes it, but I'm also disappointed that they took away a LSD in the Expy's.

 

The idea of using the vehicle’s brakes to transfer torque is not new. It has been around for a very long time. Farmers have been known to use the independent brakes on their farm tractors to transfer torque as well as to help the tractor turn more sharply.

There is always going to be a need/want for mechanical traction assist (i.e. limited-slip differentials and locking differentials) but traction control renders a limited-slip differential redundant. This is mainly why Ford discontinued the optional LSD for the Expedition.

Notable 4x4s, like the military grade civilian Hummer H1 use traction control to control drive-wheel slip and to transfer torque. The legendary Land-Rover Defender and Land-Rover Range Rover also use traction control.



The extremely off road capable 2008-present Toyota Land Cruiser (J200) uses nothing but traction control, the front and rear differentials are open type.



In a head-to-head comparison, traction control (TC) will always be better than a limited-slip differential (LSD).

● With TC, there is no LSD clutch pack to ware out and less parts mean less complexity and enhanced durability
● TC will never lose its effectiveness over the life of the vehicle
● TC will always be able to transfer the maximum amount of torque
● TC can engage and transfer torque faster than a LSD
● TC reduces stress on the drive axles

Traction control is also cheaper to implement, which is why auto manufacturers love it.

 

Awesome post sir. And, there is no upcharge for a vehicle equipped with TC. My 2010 Ford Focus has it, simply push a button and it's there.

 

If you don’t like the idea of the computer overriding your throttle input, you’re not alone.
Reducing the throttle can be bad, if say you’re off road and you need full engine power (torque) to traverse rough terrain.

The Ford Expedition’s traction control system (TCS) works in two-ways, either independently or together, via engine traction control (ETC) and brake traction control (BTC)

Engine traction control uses the engine management system of the Triton V8. It overrides the drivers throttle input (as you MCDavis) pointed out. Then it proceeds to reduce the engine throttle by retarding the camshaft timing.

Not to worry, this portion of the Expedition’s traction control system can be completely disabled, freeing the Triton V8 to produce unrestricted power (torque). The brake traction control will continue to function, to limit drive wheel slip (spin) and to transfer torque.

To disable the engine traction control (ETC) requires reading the owners manual as the system is disabled differently depending on the model year.

For example:

The 2010 Ford Expedition 4x4 will partially shut-down AdvanceTrac when the ControlTrac 4-wheel-drive system is placed in 4 Low (lock) mode. All safety systems that could hinder the Expedition while off road are turned off.

● electronic stability control (ESC) – turned off

● roll stability control (RSC) – turned off

● engine traction control (ETC) – turned off

The brake traction control (BTC) system will continue to function as normal in 4 Low (lock) mode so that it can transfer torque to keep the Expedition moving, come hell or high water.



ControlTrac 4WD controls the torque front-to-rear, while traction control controls the torque side-to-side.



By the way, I'm not lecturing you MCDavis, I just write things out to explain them for people who might not understand how traction control works.

 

If this traction control is anything like the TC on my old 2001 Mustang and like my new 08 Mustangs then I don't care for it. I've had both cars out in the snow, TC has done nothing but make both cars worse to drive in the snow. The only time I've felt it valuable is in the rain. In snow I'd end up turning it off because it would suck all my power away and I couldn't get any wheel spin to keep the car going. My driveway is sloped and to get the car up the driveway in just a inch or two in snow I'd have to turn it off because the car would make it halfway and lose all its power and slide backwards down.

 

You’re thinking of engine traction control (ETC) which reduces throttle (power).


The Expedition uses brake traction control (BTC) and engine traction control (ETC).

engine traction control (ETC) can be turned off on the Expedition (see my above post)

brake traction control (BTC) does not reduce engine throttle, it uses the ABS brakes to transfer torque, giving the exact same performance as having a limited-slip differential (LSD).

 

May I assume that I need to set the switch to 4x4 Auto to gain full benefit of all these? I predominantly run in 4x2 rather than 4x4 Auto but switch to it in heavy rain, snow, etc.

Oh, there is no Hummer H1, or any other Hummer in the military. We still have a lot of HMMWVs, though. Pronounced Hum-Vee.

-- Chuck

 

This is the operational procedure for ControlTrac on the 2010 Expedition. The operational procedure on how to turn off engine traction control varies with the model year. What model year Expedition do you have?

2 High mode:

2-wheel traction control (ABS brake application)
enigne traction control (engine power reduction)
elecontric stability control (ESC)
roll stability control (RSC)

Auto (unlocked, variable) mode:

4-wheel traction control (ABS brake application)
enigne traction control (engine power reduction)
elecontric stability control (ESC)
roll stability control (RSC)

4 High (lock) mode:

4-wheel traction control (ABS brake application)
enigne traction control (engine power reduction)
elecontric stability control (ESC)
roll stability control (RSC)

4 Low (lock) mode:

4-wheel traction control (ABS brake application)







I meant to wright "military grade civilian Hummer H1"

 

I'm pretty sure I read a long time ago about it and the brakes do the same thing on my Mustangs as your explaining, I know for sure it pulls engine power. I don't remember for sure though. I would think that it would be hard on your pads and rotors if you need your TC a lot.

 

Pads and rotors suffer from heat, and heat comes from repeated high-speed stops. A caliper squeezing a rotor at 8 mph for few seconds shouldn't hurt much.

Truthfully, if you need traction control that much you actually need more appropriate tires or a lighter pair of shoes! Any time the TC kicks on you are exceeding the vehicles capabilities. We all know you can do that a little, but do it repeatedly and something's going to go wrong.

In very un-scientific testing, our AWD BMW wagon with traction control and mediocre all-season tires is much better at climbing an ice-covered hill from a standstill than my mighty '97 F250 can with it's old-style 4wd. Mind you, I love my manual locking hubs and a lever I can push with my foot if need be to engage the 4wd, but in reality technology seems to be beating tradition. I expect our Navigator to perform similarly.

Oh, and if you hold the traction control button down for awhile it will do a great one-wheel peel!