anyone use terrain mode off road yet?

[SummitWhiteT1]

Wondering if anyone has used it at all yet. Worried that the transmission or brakes might overheat

[c.schill]

I used it for a couple minutes on a trail in PA just to see what it was like. Just felt lot of engine braking and the system electronically applying the brakes when not touching the gas. Going less than 5 miles per hour, and letting off the gas, it brings you to a stop pretty fast. Not sure it's much more useful than 4 high, but I didn't use it in any type of terrain that would warrant 4 low, or this new mode made to mimic it, so I can't speak to that. Just wanted to see what it did. From reading, it's supposed to mimic the gearing, shift points, and "crawl" effect of 4 low, but with none of the torque benefits of a true 4 low system.

[SummitWhiteT1]

Yeah same here. I tried it on a dirt road and it has some cool tricks but I just wonder if it can handle light trails especially going up or downhill. I wish someone like TFL Truck would take one off road just to see how it does lol. I don't think the torque should be a problem since these trucks already have way more torque than a lot of older trucks that did fine off road. I just worry about the transmission or brakes over heating going up and down hills.

[c.schill]

Agreed. Might be worth sending the TFL guys an email to see if they can get access to a single speed transfer case truck to do some testing. 

 

EDIT: I sent the TFL guys an email to see if they'd be interested in doing this kind of review for us.

Edited October 5, 2020 by c.schill

[SilveradoRST]

Funny enough, I emailed TFL last Nov asking about the Terrain Mode and having them test it.  They said they tested it and it's pretty basic.  Advised me to just get 4lo if I can afford it.  I found the video in which they gave it a whirl.  Not much of a test.  Just a quick demo of what it was.  I'll try to find the video again.  I wish they did a full review of it going over some of their usual off-road challenges.

[Transient]

Funny this question is being asked. I was just looking into offroad trails in San Diego to take my truck on

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[c.schill]

3 hours ago, SilveradoRST said:

Funny enough, I emailed TFL last Nov asking about the Terrain Mode and having them test it.  They said they tested it and it's pretty basic.  Advised me to just get 4lo if I can afford it.  I found the video in which they gave it a whirl.  Not much of a test.  Just a quick demo of what it was.  I'll try to find the video again.  I wish they did a full review of it going over some of their usual off-road challenges.

I didn't know they'd done anything with it yet, that's promising I suppose. In my email, I asked specifically if they would consider doing a full offroad test on some low difficulty trails/terrain with a Silverado or Sierra with this single speed transfer case. It would be interesting to see them take one on a low difficulty trail out there. I think it's Tombstone hill, they call it, that they test a lot of things on. That would be a pretty decent test scenario.

[SilveradoRST]

1 hour ago, c.schill said:

I didn't know they'd done anything with it yet, that's promising I suppose. In my email, I asked specifically if they would consider doing a full offroad test on some low difficulty trails/terrain with a Silverado or Sierra with this single speed transfer case. It would be interesting to see them take one on a low difficulty trail out there. I think it's Tombstone hill, they call it, that they test a lot of things on. That would be a pretty decent test scenario.

I'm with you.  Hope they do it.

[SummitWhiteT1]

This is from GMC’s website. It seems like it could be promising but no way to know unless it’s actually tested:


Terrain Mode is designed for use in low-speed off-road driving and helps replicate the control of a traditional low-range four-wheel drive gearing. Additionally, it works to assist the driver on very technical terrain, where precise vehicle control is essential.

“Our goal with Terrain Mode was to assist the driver, but to ensure they didn’t feel isolated from the off-roading experience,” says Creehan. ”We wanted Terrain Mode’s functionality to feel natural – and above all, be enjoyable.”

In order to select Terrain Mode, the transfer case must be in four-wheel drive (4 High). A unique transmission calibration helps leverage as much engine braking as possible. Like Snow Mode, the accelerator pedal is tuned to respond slowly, allowing for a more precise application of throttle – important when trying to regulate wheelspin when climbing uneven surfaces – while Start/Stop is disabled to avoid any interruption when slowly traveling over rough terrain.

Terrain Mode also employs advanced brake-based controls to not only modulate torque across axles – important on loose or uneven surfaces – but it can also work along with engine braking to help regulate speed, especially when travelling slowly downhill.

At speeds between 10-25 mph, Terrain Mode will slow the vehicle to a creep speed, much like low-range gearing would in a two-speed transfer case. In the case of more challenging situations – like traversing small boulders or logs – the driver can manually shift the transmission into first or second gear (L1 and L2). In this case, the brake system will work to bring the truck to a full stop if the driver removes his or her foot from the accelerator.

Terrain Mode can also leverage an advanced form of Hill Start Assist, which helps hold the brakes under certain conditions while the driver shifts his or her foot from the brake pedal to the accelerator, helping prevent Sierra from moving during the transition, especially while driving through rocky terrain or steep paths.


The part about modulating torque across axles sounds particularly interesting. Sounds like the computer doing left foot braking for you to help with traction


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[Transient]

This is from GMC’s website. It seems like it could be promising but no way to know unless it’s actually tested:


Terrain Mode is designed for use in low-speed off-road driving and helps replicate the control of a traditional low-range four-wheel drive gearing. Additionally, it works to assist the driver on very technical terrain, where precise vehicle control is essential.

“Our goal with Terrain Mode was to assist the driver, but to ensure they didn’t feel isolated from the off-roading experience,” says Creehan. ”We wanted Terrain Mode’s functionality to feel natural – and above all, be enjoyable.”

In order to select Terrain Mode, the transfer case must be in four-wheel drive (4 High). A unique transmission calibration helps leverage as much engine braking as possible. Like Snow Mode, the accelerator pedal is tuned to respond slowly, allowing for a more precise application of throttle – important when trying to regulate wheelspin when climbing uneven surfaces – while Start/Stop is disabled to avoid any interruption when slowly traveling over rough terrain.

Terrain Mode also employs advanced brake-based controls to not only modulate torque across axles – important on loose or uneven surfaces – but it can also work along with engine braking to help regulate speed, especially when travelling slowly downhill.

At speeds between 10-25 mph, Terrain Mode will slow the vehicle to a creep speed, much like low-range gearing would in a two-speed transfer case. In the case of more challenging situations – like traversing small boulders or logs – the driver can manually shift the transmission into first or second gear (L1 and L2). In this case, the brake system will work to bring the truck to a full stop if the driver removes his or her foot from the accelerator.

Terrain Mode can also leverage an advanced form of Hill Start Assist, which helps hold the brakes under certain conditions while the driver shifts his or her foot from the brake pedal to the accelerator, helping prevent Sierra from moving during the transition, especially while driving through rocky terrain or steep paths.


The part about modulating torque across axles sounds particularly interesting. Sounds like the computer doing left foot braking for you to help with traction


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It also sounds like they are utilizing what's known as a retarder when they say, "A unique transmission calibration helps leverage as much engine braking as possible.". A retarder works in the transmission to create the affect of engine breaking, but doesn't create the loud noise diesel engines are known for when an engine brake, aka jake brake, is utilized. GM has been manufacturing retarders for decades, mostly in commercial busses made by Gillig. Anybody that has experience driving a Gillig bus (Low Floor or Phantom) can tell you retarders can make for bad situations in slick conditions like snow or ice. As long as there's grip it'll be okay to use, but a retarder can take a slick situation and make it worse.

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[c.schill]

Got a reply from TFL this morning. Here's what they said...

 

Hi Chris,

Thanks for the note. Our ability to test trucks is limited to the models that manufacturers supply to us. Since they know we take anything with AWD/4WD off-road as part of our reviews, we nearly always get the Z71/Trail Boss versions of trucks to review. So it's not a matter of would we, but can we.

Still, if a 4x4 Silverado that's not a Z71 or Trail Boss comes our way, we'll run it off-road. Count on it.

Best,

Grant

 

So sounds like they don't really get a choice in what GM sends them to use for testing.

[SummitWhiteT1]

guess we are going to have to wait until some brave soul out there decides to take one out on a more rigorous trail lol

[Monte1978]

On 10/5/2020 at 3:56 PM, SilveradoRST said:

Funny enough, I emailed TFL last Nov asking about the Terrain Mode and having them test it.  They said they tested it and it's pretty basic.  Advised me to just get 4lo if I can afford it.  I found the video in which they gave it a whirl.  Not much of a test.  Just a quick demo of what it was.  I'll try to find the video again.  I wish they did a full review of it going over some of their usual off-road challenges.

I got 2020 gmc sierra with single speed if anyone makes a video of your 2 speed doing anything I'll do it in my single speed I ain't scared

[Gangly]

Interesting about the "Retarder", I was unfamiliar with the term but I understood there had to be something to limit the transmission other than brake application.  Always fun when you learn something new, now to go research it