When to lock the Torsen center differential (H4L)?

ScoMey said:

Try as I might, I've never really been able to get the back end of my Limited to really kick out while applying power and turning ... and the one time I did, the VSC nanny kicked in and ended the fun pretty quick. :zoom:

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When I had the stock tires I got it to break loose on a slick wet snow, it started in the back and then the front, Hal took over but I was surprised how much it moved. With my current tires it doesn't seem to matter what I do and it sticks. I have slowed down a bit as the kids are in the car most of the time. But I drive to the mtns a ton through winter so always looking for knowledge.

NoDak said:

1. awd will never have a 4L
2. most awd/4wd (Im looking at you rav4) are hybrid designs. they are primarily fwd mode until slip then transfer power to the other wheels
3. the LE is a FT 4wd system
4. Subaru asym awd is like the LE system w/o the 4L
5. the wrx sti is the perfect marriage of 4wd and awd, iirc, they have lockable CD and RD.

this is what I remember from numerous readings across a lot of different post and articles.

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regarding 1, i had a 2003 kia sorento that had two options

1. awd where the back wheels were the primary movers and the front would assist when the back lost traction

and

2. 4L. and it was truly 4L.

so i know its rare but its out there

JayceeP said:

I completely agree. I actually didn't learn until reading another thread a couple of weeks ago that a locked center diff = same as putting a 2wd vehicle in 4wd manually. This is how my Jeep Wrangler 4door worked and I felt it had noticeably more bite in the snow. This year, I will be locking the center diff on snowy days.


When I had my Jeep I preferred no traction control most of the time when in 4wd. I found it worked really well in 2wd however. I do notice that traction control re-engages in the 4R at those speeds. Is there any way to fully disable the system? In the Jeep if you pushed the traction control button, it turned off. But if you held it for 5 seconds, it turned off everything. That equalled a LOT of fun.

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on the 2014+ 4unners, if you push the vsc button it will disengage the vsc up to 25-30 mph and re-engage automatically. this can be done at any speed below 25. this also applies to other awd /4wd vehicles made by Toyota.

at a complete stand still in gear or parked, if you push that same button for 5-10 seconds it will completely turn of vsc until you turn off the vehicle. I use this mostly and engage the center diff as needed.

NoDak said:

on the 2014+ 4unners, if you push the vsc button it will disengage the vsc up to 25-30 mph and re-engage automatically. this can be done at any speed below 25. this also applies to other awd /4wd vehicles made by Toyota.

at a complete stand still in gear or parked, if you push that same button for 5-10 seconds it will completely turn of vsc until you turn off the vehicle. I use this mostly and engage the center diff as needed.

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It's the same for mine. It automatically turns vsc back on at those speeds which is annoying. I'll hold the button longer next time. Is there a different indicator that comes on to confirm you disengaged it successfully?

I went out and tested locked vs unlocked center differential in a snowy parking lot today. I have a 4th gen with no VSC Off switch, so they way it works is VCS is on and the center differential is unlocked, or VSC is off and the center differential is locked. I tested both in 4H.

With it locked I mostly got understeer, but I could get it to oversteer sometimes. When it was understeering, giving it some gas didn't help get me going in the direction I wanted since the back wheels had traction and the front wheels were sliding sideways. Giving it more gas could work since it would kick out the back wheels, but then you are in a four wheel slide, which may not be desirable.

With it unlocked, I could get it to oversteer a little sometimes, and it would rarely understeer. Sometimes it felt like it was sliding sideways (four wheel slide). VSC seems to kick in more aggressively if you turn the wheel straight or the other direction while sliding. If there's just a little over or understeer it doesn't help, and it doesn't seem to do anything about sliding sideways, though I'm not sure it could. I could slide enough without VSC helping that I wouldn't say it was responsible for the difference in handling between locked and unlocked.

I never got the back end to really swing around in this mode, though I was trying to be somewhat cautious so as not to hit the street lights in the parking lot. It did swing out a couple times with the center locked.

Overall I prefer the center unlocked for around town driving on snow. It's much less likely to understeer or spin out, and VSC usually helps more than it gets in the way. For driving on the highway where you don't typically have to make turns, having the center locked might be better? I think if you are sliding on a snowy road, you are going too fast because although you might be able to make your turn the way you intend, you won't be able to brake or react to things as quickly as you need to, and you aren't fully in control of your vehicle. If one wheel were to hit a dry spot it could spin you around. It's better to go at a speed where all four wheels can keep traction, and you can stop and turn like normal. If you want to go faster for some reason, get snow tires.

If you have both options and you don't know which one to use, go try them out and see which one you like better.

m85476585 said:

I went out and tested locked vs unlocked center differential in a snowy parking lot today. I have a 4th gen with no VSC Off switch, so they way it works is VCS is on and the center differential is unlocked, or VSC is off and the center differential is locked.

If you have both options and you don't know which one to use, go try them out and see which one you like better.

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Yup, after the discussion on this thread and fresh snow I went out to play and tried a number of corners with the center diff locked and unlocked and I'm going to agree that unlocked is better. I did tend to get more slip with it locked through the corners, I was not babying it either. All around town stuff no highways for this testing.

On the 5th gen limited VSC is still on even when locked. You can turn it off If you want.

Jhalko said:

Yup, after the discussion on this thread and fresh snow I went out to play and tried a number of corners with the center diff locked and unlocked and I'm going to agree that unlocked is better. I did tend to get more slip with it locked through the corners, I was not babying it either. All around town stuff no highways for this testing.

On the 5th gen limited VSC is still on even when locked. You can turn it off If you want.

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Yes, this will be my strategy too. Take it out and play. I've had my '14 for a year now, and have had it in 4Locked a number of times just to exercise it. But I've never found the time when I thought to myself "I need to lock the CD."