[vskis]

Does anyone else have their ZR2 disengage the rear locker above 25 MPH while in "off road mode"? The ZR2 specific supplement manual states that it should stay engaged at any speed, as long as you have off road mode on.

I've only had my 2018 ZR2 for 2 weeks, so maybe I'm missing something? In particular, I'm trying to keep the rear diff locked in 2 HI, with traction and stability control completely off, and only when driving off road. I've tried various traction/stability control settings combinations, as well as changing up the order in which I enable offroad mode, turn off traction control, engage the locker, etc... None of these other settings should matter with this issue, but I keep getting the "reduce speed to use locker" message on the dash no matter what I try.

In fact, I don't notice any change in shift strategy, or the "sport" traction/stability control feature that you're supposed to have in off road mode. All I get is that little light on the dash!

I'm going to take it to the dealer and see what they tell me, but I wanted to check in and see if anyone else experienced this issue. I'll update once I find a fix.

 

[vskis]

By the way, here are some pics of my ZR2! This is the new (kinetic?) blue for 2018. Really happy with the truck so far!

 

[KMW]

Sounds like something is wrong with yours. You don't have to do anything special to get it to work. Just push the off-road-mode button, and your locker will engage and stay engaged. That's it.

As for the change to shifting, it's pretty noticeable. I think it's actually just the same as tow-haul mode but with changes to the traction control and stabilitrac too. I notice it holds gears longer before upshifting. Don't really notice any change in throttle application, but I have the diesel. Might be more difference there with the V6.

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[4x4fan]

Most vehicles that have manual lockers to not work over speeds of 25mph, in addition many vehicles require that you be in 4wd low. Many also require the rear locker be engaged to use the front one. I am supprised that the ZR2 has not limit, so basically i can put the lockers on and crank it up to 100mph, does not make since to me.

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[KMW]

Most vehicles that have manual lockers to not work over speeds of 25mph, in addition many vehicles require that you be in 4wd low. Many also require the rear locker be engaged to use the front one. I am supprised that the ZR2 has not limit, so basically i can put the lockers on and crank it up to 100mph, does not make since to me.

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Well, only the rear locker, and only with Off-Road-Mode engaged. The front locker will only engage in 4WD-low range, and only if the rear is already engaged.

And you can only crank it up to 98 mph. Unless you have a tune with the limiter disabled. By the way, the Duramax has no problem hitting 98 mph.

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[4x4fan]

Well, only the rear locker, and only with Off-Road-Mode engaged. The front locker will only engage in 4WD-low range, and only if the rear is already engaged.

And you can only crank it up to 98 mph. Unless you have a tune with the limiter disabled. By the way, the Duramax has no problem hitting 98 mph.

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OK, thanks. That clears it up.


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[KMW]

Ok, I think I figured out your issue! Played with it on the way home from the gym just now.

Even in Off-Road-Mode the locker will not initially engage at speeds over 20 mph. You have to initially engage it BELOW 20 mph, then it will stay engaged until you turn it off. When I try to turn it on above 20 mph I get the "lower speed" message.

Try that and I'll bet you're just fine!

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[G2SKIER]

Exactly what @KMW said. I've played with the same scenario and you gotta lock it at low speeds. That blue looks great btw!


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[nvblue]

Why do you want to use the locker at over 25 MPH. Are you trying to power slide?

I only use lockers when I can't get traction any other way, so I've never even tried to use one that fast.

 

[G2SKIER]

Why do you want to use the locker at over 25 MPH. Are you trying to power slide?



I only use lockers when I can't get traction any other way, so I've never even tried to use one that fast.

Rear lockers are fun at speeds. Makes the rear of the truck much more tail happy.

It can be more predictable after you get used to it as well. Say you're blazing along with your foot down, and there's a little mud or loose sand under only one tire. With an open diff, it'll spin that tire up faster because there's less traction and you'll lose speed and then have one tire spinning way faster than the other when you do gain traction again. With both wheels locked together, you'll always have them spinning at the same speed no matter what. No speed lost in that situation.

Go out and play with it if you have a section of trail that you're familiar with going quicker on. Right away, you'll feel like your rear tires are on a slippery surface because it likes to kick sideways a bit more, but over time I think you'll find it more predictable.


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[fcs-04]

as a general rule even on my side by side and other trail rigs I've had I always try to engage the lockers at the lowest speed possible, once your locked hammer down. If your engaging at speed it raises the potential of there being a large velocity difference during lock up which adds stress to the entire assembly (a weak link in auto locking system such as the g80). the beauty of electric and/or air lockers is the ability to control exactly when you want the locker to engage.

 

[G2SKIER]

Exactly, every time I've locked mine in my truck I've been stopped completely. I'm too scared to lock them at speed lol


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[4x4fan]

It sounds like it more predictively let's loose.

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[G2SKIER]

It sounds like it more predictively let's loose.

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Exactly!


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[vskis]

Thanks for the help everyone! I took it to the dealer yesterday and they didn't find any faults, but reset the electronics anyway. That fixed the rear locker issue right away. I'm excited to hit up some trails this weekend!

I typically do higher speed off road driving here in AZ and find that keeping the rear diff locked in 2 HI allows for predictable over-steer during turns. The extra rotation helps with tighter turns especially.

By the way, the 2017+ Ford Raptor does NOT have this feature! You can only engage the rear locker in 4WD. :rofl

I'm pretty happy the Ford dealers here refused me when I wanted to order a optionless extended cab Raptor at MSRP. Especially after seeing how capable the ZR2 can be at desert running. So far, I'm planning on installing a supercharger along with a 1" lift and 33" tires. Going to keep it stock for at least a few more months though!

 

[CrashFix]

I'm trying to keep the rear diff locked in 2 HI, with traction and stability control completely off, and only when driving off road.

Does the ZR2 have a 2Lo mode?

Well, only the rear locker, and only with Off-Road-Mode engaged. The front locker will only engage in 4WD-low range, and only if the rear is already engaged.

I thought you could engage the front locker by itself, is that not the case?
.

 

[KMW]

Does the ZR2 have a 2Lo mode?



I thought you could engage the front locker by itself, is that not the case?
.

No, there is no 2WD low. And no, front locket only engages if the rear is engaged.

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[Dan Mackin]

Per this article there's a way to turn off traction control completely in 2WD with the rear diff locked and no speed at which it unlocks. I like to call this "******* Mode" and I had a hell of a time with it on the beaches at Lake McConaughy!

I (mistakenly) thought that this was required to keep the rear diff from unlocking over 25 mph. I see now that it just requires "Off Road Mode" and a locked rear diff for that to be the case. TIL.

 

[G2SKIER]

Per this article there's a way to turn off traction control completely in 2WD with the rear diff locked and no speed at which it unlocks. I like to call this "******* Mode" and I had a hell of a time with it on the beaches at Lake McConaughy!



I (mistakenly) thought that this was required to keep the rear diff from unlocking over 25 mph. I see now that it just requires "Off Road Mode" and a locked rear diff for that to be the case. TIL.

I love this mode! That’s what I’m in all the time offroad unless I can’t make it up a hill


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[vinnier6]

Is there a ZR2 specific owners manual? I only have the standard manual...

edit:

I found it, it was in the glove box with the other stuff, it was so thin it was in between some other stuff...