so what is this "rear locker" thing for?

[P. A. Schilke]

I've always associated torque vectoring with all wheel drive cars where the center differential is torque vectoring and can change the torque split. For instance, if the front is spinning, then the differential can reduce torque to that axle, and apply more torque to the rear that isn't spinning.

Side slip, steering angle, and g-force are usually associated with stability control where a vehicle in a turn starts to either become loose or tight (oversteer or understeer). Individual brakes are applied, and power could be reduced in an effort to regain control and finish the turn as intended. GM used to call it active handling, and I can testify that it works.

Traction control can be either off road or on road, on high grip surfaces, or slick surfaces. Wheel spin is detected and the system will apply brake to that wheel and could also reduce power in an effort to maintain traction. Late model Vettes and Mustangs have traction control and I don't know anyone in their right mind that takes either for serious off roading. Well, not on purpose anyway.

Rangers have AdvanceTrac that includes Roll Control in addition to stability control and traction control. Apparently, the system monitors roll motion and will apply a wheel brake or wheel brakes to prevent roll over. It doesn't appear to care if any wheel looses grip. I haven't tested this feature.

I understand terrain management and trail control as described.

Hi James,

You jogged my memory to another back story.... I managed Ford On road racing and Off Road racing...Off road for my last 25 years before I retired. This is relative to ABS. As we at Ford piloted ABS, I went to my off road teams to inquire if it was a competitive advantage for our teams. There were many "I have no idea", but Enduro Motorsports driver Dave Ashley enlightened me. ABS has no place in off road racing. When you slam on the brakes the ABS releases the wheels to prevent lockup....however...off road..slam on the brakes and lock the wheels...the dirt builds like little plows under each wheel and you will stop significantly faster and in shorter distance than ABS. So lesson learned that there times when old school wins out.

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired

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[Gizmokid2005]

Hi James,

You jogged my memory to another back story.... I managed Ford On road racing and Off Road racing...Off road for my last 25 years before I retired. This is relative to ABS. As we at Ford piloted ABS, I went to my off road teams to inquire if it was a competitive advantage for our teams. There were many "I have no idea", but Enduro Motorsports driver Dave Ashley enlightened me. ABS has no place in off road racing. When you slam on the brakes the ABS releases the wheels to prevent lockup....however...off road..slam on the brakes and lock the wheels...the dirt builds like little plows under each wheel and you will stop significantly faster and in shorter distance than ABS. So lesson learned that there times when old school wins out.

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired

I've run into the same thing in the winter in Michigan. There's been quite a few times I'd have preferred for snow piles under the wheels instead of ABS.

I'm really frustrated that the AdvancTrac system can't be actually deactivated in our trucks, even with the long press to disable it kicks it a lot more than I'd like, mainly off-road.

 

[Edibrac]

A long press turns off ADVANCETRAC on mine and switching to 4L also shows the pop up that it is off. Some manufacturers still keep some systems on when you turn off TC or stability control so I can't say if it is fully off. Seems like it is.

 

[Gizmokid2005]

A long press turns off ADVANCETRAC on mine and switching to 4L also shows the pop up that it is off. Some manufacturers still keep some systems on when you turn off TC or stability control so I can't say if it is fully off. Seems like it is.

It's not. I can confirm with multiple different variations that 4H/4L/2H and AdvancTrac off doesn't entirely disable things like traction control.

 

[krisrayner]

I owned an older Audi 100 for a while that had an ABS disable button. I was confused as to why, but the owners manual explained the exact scenario you talked about but in snow conditions. Guess they don't trust drivers to figure that out anymore.

Hi James,

You jogged my memory to another back story.... I managed Ford On road racing and Off Road racing...Off road for my last 25 years before I retired. This is relative to ABS. As we at Ford piloted ABS, I went to my off road teams to inquire if it was a competitive advantage for our teams. There were many "I have no idea", but Enduro Motorsports driver Dave Ashley enlightened me. ABS has no place in off road racing. When you slam on the brakes the ABS releases the wheels to prevent lockup....however...off road..slam on the brakes and lock the wheels...the dirt builds like little plows under each wheel and you will stop significantly faster and in shorter distance than ABS. So lesson learned that there times when old school wins out.

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired

 

[scubasteve278]

Rear locker is for any situation that momentum is king. In my last truck ('12 TRD Tundra), there was no locker, only LSD. I cant tell you how disheartening it is to be in 4wd, trying to keep momentum to make it up steep hills off-road in the snow just to feel the power being robbed from underneath you as the ABS and traction control kicks in. In the Ranger, you can turn Trac off (I know not fully) and lock the rear-diff and the feeling is totally different. You put your foot to the floor, and it delivers power the whole way through until you let off, saving yourself from having to attempt to back down 11km of road that is now deeply tire trenched from you on the way up and getting extremely stuck, then having to leave the truck for 2 nights until you can finally convince a friend with a capable vehicle to attempt to make it up to it to pull you out...ask me how I know...My rear locker has already saved me in a few situations in the few months ive owned my ranger, but in my mind its important to have it on before you need it in order to maintain the forward momentum. It also helps in situations that others have pointed out, when you have both 1 front and rear wheel off the ground and the open diff is not sending enough power to the wheels on the ground.

 

[DHH]

Now that this thread has been brought back up, it reminded me of several winters ago when I bought my 1st truck that had a traction control system.
I was going up a snowy/icy road and had it in 4x4, but got stuck. Sitting there on the side of the road, I (embarrassingly) watched several vehicles go right by.....including Porsche & Mercedes cars.
I got out after a guy came by with a bucket of sand. It wasn't until I got home that I remembered about the traction control. With it on, the computer kept slowing the wheels down to try and get traction. Eventually they just stopped turning.

 

[Megawatt]

I can add a little to some of this discussion. Your gonna have to forgive the Jeep pics of mine but the pics should help a lot with what I’m trying to say. My FX4 is on order so no ranger pics yet.

I’m not going to quote from the other pages but I will just say a rear locker is my choice over terrain management. TM is great for what it is but a locker is the real deal.

Pics are of me and other Jeeps climbing a hill. Very basic stuff but if your new to 4wheeling it looks intimidating.

That is the small hill we will climb. 4lo and rear locker engaged. On the way up the weight will be shifting side to side as we climb onto different rocks and have an occasional wheel in the air.

Im at work so I will make a couple entries in a min with more pics as we go up the hill. ........

 

[Megawatt]

Jeep in front of me so you can see a reference to angle and size of ruts.

If TM was used when a wheel gets in the air or very light in traction it would spin faster than other axle that has all the weight on it. The Computer would apply the brake to the faster spinning wheel to try to send power to the wheel with all the weight on it and help you move forward. Your momentum would be very jerky and most likely start to lurch up the rock face.

Bouncing up the hill in a jerky jerky motion is a good way to break or damage components. Smooth is drama free and better control.

 

[viperwolf]

I can only give an example. Two times that rear diff lock has saved me in the sand. Even though I have a 4x4, sometimes the computer cannot figure the right traction path. Locked the diff and it practically walked out. Im not sure I understand why, Im assuming bc of the floating nature the sensors where Calculating things wrong for that circumstance.

I could also guess:
That when the 4x4 is activiated which is differnt than the AWD it has. It will put more power to the wheel that has the most traction. In the case of sand, you need all 4 wheels to turn to get that type of traction. Im only guessing though. Which is why the rear diff made a big difference for me.

 

[Megawatt]

The rear locker made this hill a very easy climb. Both rear wheels turned at same speed and when one tire was In the air the loaded wheel pulled the Jeep forward until both wheels could contribute to the forward movement. The rock face has gravel and because the locker was on it didn’t matter if one wheel was on gravel and the other on dry rock. It was a steady momentum constant climb. TM would get you over also but not a smooth constant ride like a locker would.

Once I crested the top I would take off the locker. I only engage it for the climb. I used it for 30 seconds from start to finish. A locker is a temporary use item to get you past an obstacle. In the 7 years I had my Jeep I probably used the locker for 10 minutes if you add up all the locked time.

Now, before someone says they would not do that with their ranger. We had a stock Tacoma 4x4 with no locker in our group. He made the same hill up and over. He scraped and spun and hopped but he got over. A Ranger can clear this hill. You may not be able to but your Ranger 4x4 can.

 

[charwest]

T

The rear locker made this hill a very easy climb. Both rear wheels turned at same speed and when one tire was In the air the loaded wheel pulled the Jeep forward until both wheels could contribute to the forward movement. The rock face has gravel and because the locker was on it didn’t matter if one wheel was on gravel and the other on dry rock. It was a steady momentum constant climb. TM would get you over also but not a smooth constant ride like a locker would.

Once I crested the top I would take off the locker. I only engage it for the climb. I used it for 30 seconds from start to finish. A locker is a temporary use item to get you past an obstacle. In the 7 years I had my Jeep I probably used the locker for 10 minutes if you add up all the locked time.

Now, before someone says they would not do that with their ranger. We had a stock Tacoma 4x4 with no locker in our group. He made the same hill up and over. He scraped and spun and hopped but he got over. A Ranger can clear this hill. You may not be able to but your Ranger 4x4 can.

That makes sense. I definitely appreciate that the TM system is hesitant and occasionally jerky when negotiating difficult obstacles. I have been operating with the mindset: drive the car and if I get stuck, consider the locker. And I have yet to have to resort to the locker.

But it sounds like the locker might smooth things out for the times where forward momentum matters (uphill snow, sand, super steep rock crawling) so maybe we will try that out in the future.

 

[LostMy65]

I didn't think my question needed its own thread.
I bought 4x4 mainly for boat ramps and we get some snow, but mainly icy roads.
I'll probably never do serious off roading.
Should I have gotten the rear locker?

 

[D Fresh]

It's not. I can confirm with multiple different variations that 4H/4L/2H and AdvancTrac off doesn't entirely disable things like traction control.

This is incorrect from my experience.

If you've turned off AdvanceTrak and are still experiencing nanny intrusion, you are activating RSC. Roll stability control can only be deactivated by switching your TM system to Sand Mode.

In my truck, AdvanceTrak and traction contol off, RSC is the only thing that will activate, it will pull power AND apply some brakes one you're more than about 10-15° sideways.

Get yourself to a low traction situation, turn off AdvanceTrak and Traction Control, put your truck in Sand Mode and let 'er rip tater chip. You'll get some play time without the nannies interfering.

 

[LostMy65]

I didn't think my question needed its own thread.
I bought 4x4 mainly for boat ramps and we get some snow, but mainly icy roads.
I'll probably never do serious off roading.
Should I have gotten the rear locker?

I think this answers my question:
https://rigforge.com/do-lockers-help-in-snow/

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