Changes in the 4wd system on new Expedition

michguy

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I have had three Expeditions (98,04, and my current 08). So I am used to the 2H, 4A, 4H and 4L set up. But the new Expeditions (for the first time) now have single range rather than high-low range transfer cases. So now you have just 2H (2wd) and 4A (4 auto) settings unless you elect either the FX4 off road package or the Heavy duty trailer tow package, in which case you get a two speed transfer case adding a 4L setting and, in addition, a 3.73 electric limited slip differential. There is no longer a 4H setting regardless of how the Expedition is configured.

So I have a couple of questions to hopefully some that have used their new 2018's in the snow or off road. In the past I have used 4A for normal road use when road conditions are questionable, as they often are in Michigan. If the snow is heavy or I am on one of our trail roads at deer camp I have used the 4H setting. I admit to essentially never using 4L.

First question: Is the loss of the 4H mode significant, or do the new terrain settings adequately substitute? Second question: For those that have either of the two packages mentioned above, does the limited slip differential really do anything that the old system failed to do? And does the lower axle set up (3.73 vs 3.3) significantly impact vehicle gas milage. If so, by how much? I believe that the F150's continue to use a two speed set up essentially the same as in previous Expeditions, which makes me wonder if the set up in the new Expedition is as "robust" as that used previously.

Eventually I would hope to place an order. However, I have attempted to get technical answers to these questions from Ford, but no one has been able to answer or get me connected to anyone with the appropriate knowledge base, which is incidentally, very frustrating for long time Ford customer. Any help would be kindly appreciated.
 

shane_th_ee

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For a 4H only user, you’ll never see a difference if you lose the 4L. 4L is useful for rock crawling and very slowly descending steep and slippery slopes as engine baking will keep the truck moving very slowly without the driver needing to touch the brakes. The locking limited slip rear differential means you’ll never get stuck trying to start if opposing corners don’t have traction. Does your existing Expedition have the limited slip rear differential? If it doesn’t and you’ve never had an issue with it, you’ll be fine with the open differential. The other thing you’d lose going to the “4A” only four wheel drive system is the “neutral” mode which lets you tow it without a dolly. I just ordered an FX4 this past week, so I can’t comment on the gas mileage difference between the two rear axles.
 

deweysmith

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In my 2012's manual, 4H says it splits the torque 50/50 between the front and rear in 4H under MOST conditions. It still has the freedom to shift it back and forth as necessary, the difference being between 4A and 4H is that you'll get driveline windup/binding when cornering if you're in 4H on dry pavement.

4A is fantastic for most usage. I thought it would light up the traction control light when it was shifting power around, but it doesn't. It will shift power between the axles as needed and probably before you even notice the rear axle slipping. I tried it out a few weeks ago at the Utah sand dunes. It would slip, but eventually get going in 2H, but in 4A it could get going on sand with very little throwing of sand before it applied power to the front wheels to. Pretty awesome.

I don't have a 2018 but I bet the terrain selection system allows it to preselect a torque split value optimal for most conditions you give it, but it will still adjust the split as needed.
 

Meeker

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I'm about to order a 2018 XLT, and I have a question for you guys. Is there any difference in the 4x4 system if you choose the FX4 package or the Heavy Duty Trailer Towing package? Do you get the same terrain options in the dial menu?

I believe you can select the 3.73 Limited Slip rear axle as a standalone option with the HDTT package. Do you then end up with the same drivetrain as FX4? Obviously the other FX4 stuff would be missing (skid plates, shocks, radiator).

Hey, why wouldn't you want the bigger radiator with the trailer towing package anyway? Inquiring mind wants to know.
 

shane_th_ee

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I'm about to order a 2018 XLT, and I have a question for you guys. Is there any difference in the 4x4 system if you choose the FX4 package or the Heavy Duty Trailer Towing package? Do you get the same terrain options in the dial menu?

I believe you can select the 3.73 Limited Slip rear axle as a standalone option with the HDTT package. Do you then end up with the same drivetrain as FX4? Obviously the other FX4 stuff would be missing (skid plates, shocks, radiator).

Hey, why wouldn't you want the bigger radiator with the trailer towing package anyway? Inquiring mind wants to know.
The upgraded center differential (really a transfer case), the 3.73 rear axle and the heavy duty radiator are all included in BOTH the FX4 package and the Heavy Duty Trailer Tow package. What you're really choosing between those packages is skid plates, shocks and trim items (wheels, running boards, etc) OR integrated trailer brake controller and the pro trailer backup assist. Note further that the trailer brake controller can be added as a $495 (US) dealer installed option. Finally, if you do want it all, you can get the FX4 package and the max trailer tow package price drops to $1100 (US) since it only includes the trailer brake controller and the pro trailer backup assist...
 

powerboatr

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Does that make the Expy Max the world's largest dinghy?
mine is .
we tow it on the hauler or the ground
main reason we have 4x4 like the 150 it replaced was the having the ability to tow it on the ground.
but it rides on the trailer 99% of the time, really cuts tailgaters

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