4WD Failure in sand (hill assist/descent faults warnings)

Discussion in '4th Gen - 2018 - present' started by DCS_express, Jun 30, 2018.

  1. DCS_express

    DCS_express Member

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    Obviously I will be taking it back to the dealer, but wanted to see if anyone else had similar issues.

    I drive occasionally on the beach here in Florida. There is one particular beach that is 4WD only and has really soft beach sand. Both times I have driven there after 100-150 yards my 4WD starts totally going haywire. The beach is totally flat there are no hills or dunes or anything just soft sand.
    Trip 1. Just put in 4A and didn't change the driving mode. After driving approximately the distance stated above the truck started binging at me and telling me that the hill start assist warning and a hill descent fault has been detected.
    Trip 2. Changed driving mode to sand. Same story. . .after driving the approximately the same distance again things went totally haywire. The following 5 things happened
    1. hill descent fault
    2. hill assist warning
    3. driving mode automatically changed to normal which turned off the 4 wheel drive
    4. unable to change driving mode out of normal
    5. something about traction control (I don't remember exactly)

    So there I am stuck on the beach unable to put it back into 4WD at least through a driving mode. Luckily was was able to press the 4A button and lock the differential button to get off the beach, but as far as I am concerned it was a total failure. I need a reliable 4WD system otherwise my 65k vehicle may get washed away by the rising tide. In my opinion the 4A doesn't work to well in soft sand - it seems like it waits too long to kick in and your tires are already starting to dig into the sand before it engages.

    Any one have similar issues or any thoughts?
     
    Last edited: Jun 30, 2018
  2. stamp11127

    stamp11127 Super Moderator Staff Member

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    1) Make a video of the problem since the dealer can't/won't replicate the problem.

    2) Have the dealer test it on the beach - when it is stuck then they will acknowledge a problem.
     
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  3. DogDad

    DogDad Active Member

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    Interesting. I’m looking forward to testing mine in the sand on the beaches in the Outer Banks of North Carolina. I hope I have better results.
     
  4. proeasy

    proeasy Full Access Members

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    Few weeks ago had mine a few times at the state park in Amelia Island FL. 4WD was required to go on the beach. At first it is compact sand, but you soon enter some rather deep sugar sand. I was in 4A standard mode and you could feel the traction control intervene in the deep sand. on the fly shifted to sand mode and locked the rear axle. World of difference. Then came to a full stop to try 4 Low. The park has some deep sand and the truck was outstanding in the deep sand. Performed much better than my former Yukon Denali would have, older version with single speed full time AWD. GM now puts a selectable transfer case in them
     
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  5. DCS_express

    DCS_express Member

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    Dogdad - When everything is working it goes through the sand pretty good. I hope you have better results too - I used to live in Hatteras - the sand up there is definitely more challenging/deeper ruts than what I am driving through down here. Lot's of people there bag their tires (take air out of them) to get through - we generally don't have to do that down here.

    Proeasy - funny you should say that - the south end of Amelia Island is exactly where all of this is happening. 100% agree with sand mode working very good there and also agree it is much better than 4A. In 4A you can feel your wheels starting to dig in and spin in the sand and feels like you are about to be stuck and then you feel the front kick in and it pulls right out.
     
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  6. DCS_express

    DCS_express Member

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  7. proeasy

    proeasy Full Access Members

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    Some early European entrants in the SUV market relied only at first on all open differentials (center, front and rear) and the Traction Control system to regulate torque to the wheel based on wheel slip.

    Many would go into limp mode say climbing snow covered roads to the places such as ski resorts. Many now have active center and eLSD rear axles to keep the power flowing prior to brake intervention
     
  8. Adam Huskins

    Adam Huskins Well-Known Member

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  9. DCS_express

    DCS_express Member

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    Took to the dealer the video came in very handy. They sent a request for input from Deaborn, MI. I will keep all posted - but right now I think I am the unlucky person with a very uncommon isssue. Or maybe they just didn't make many XLT's with 4WD and the tow package and 18 inch wheels for people that drive on the beach . . . .
     
  10. scottdm

    scottdm Full Access Members

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    Thought I'd resurrect this thread on driving in the sand. Just got back from the Outer Banks, NC and spent some time at the Cape Hatteras National Seashore with the Expedition. Overall, I was very pleased. I'm running 20" wheels with Michelin Defender LTX M/S tires. I aired down to 20 psi and was able to drive anywhere we needed to with a mix of hard packed and really soft deep rutted sand. Ground clearance was also fine and I didn't drag anywhere even in the deep rutted areas. I did trim my front air dam so that its even with the front skid plates, so not sure if the standard air dam would have dragged. I ran in 4A with the rear locked and didn't have any issues. The Stowaway hitch carrier worked out well on the trip, and was a good spot to keep recovery gear (VIAIR pump, jack board, Bubba Rope, Maxtrax, etc). Photos attached:

    IMG_0094.jpg

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    IMG_0096.jpg

    IMG_0097.jpg
     
    Last edited: Jul 13, 2019 at 9:38 PM

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