Differential lock on for snow/ice?

[Cumby]

Just wondering if it is necessary or a good idea to lock my center diff on my v8 4x4 when I encounter snow or ice on the road. I've read where it needs to be deep and I wouldn't think it would be good to have the tires periodically grabbing traction with the pavement.. How do you determine when 4 wheel hi is enough or to go ahead and engage center diff lock? I'd prefer not to find out I need it after I wind up in a ditch

 

[m85476585]

I prefer to leave it unlocked. That seems to give the most neutral and predictable handling, at least when I tested it in a snowy parking lot.

If you lock it, it turns VSC off, which means it won't try to help you keep going in the direction you intend to go (the direction the steering wheel is turned). But it also might reduce the throttle if it detects wheels spinning, so if you get stuck VSC can get in the way. I've already had VSC save me once on the way down a snowy mountain pass. I was going too fast, and it kicked in to keep me from sliding into the concrete barrier at the side of the road.

With it locked, I also got a lot more understeer most of the time. I would try to turn, but it would keep going in a straight line. Sometimes I would get oversteer and basically spin out. If you are trying to stay on the road, you don't want either of those things.

Last weekend I was driving off road on a snowy road. There was maybe a foot of snow, but nice deep tire tracks to drive in. With the center unlocked it was easier to stay in the tracks, and I didn't get stuck. With the center locked, I was sliding around more, and it was more difficult to stay on the line I wanted. At one point I slid out of the tracks, slowed down and lost momentum, and came to a stop. I was stuck in the sense that I couldn't go forward, even with the center locked. I didn't use 4-low because I was already spinning wheels, and the traction control couldn't get me going. Luckily I was able to back out, but I had a couple more close calls after that in some deep spots. This was snow that has been melting for two weeks, so it was soft but easily compacted into something hard. With more aggressive tires, chains, or a rear locker, I might have been able to plow through the snow without backing up.

In general 4wd won't help you much on snow and ice, except for getting going. It doesn't really help you turn or stop, so it's important to have tires with good tread, and take it easy when the roads are slippery.

 

[MikeInNH]

You want to lock it drudging through deep snow. Otherwise just keep it unlocked.

 

[t-man]

Yes, only lock it if you are trying to get across a slippery intersection or if you are going through deep stuff and the traction control is shutting you down. The reason is, the trac does an awesome job of stopping you from sliding! If you don't have it on and you start sliding you have no assistance, just hope you can straighten it out. I like to play so I frequently turn it off. lol I have personally had that traction control stop my truck from sliding and kept me from hitting another car several times, and once it was baaad out and I turned on another road. I was going really slow and careful because the road I was turning on slopes away from the road I was on, dipping towards the other lane. I started sliding sideways and if it wasn't for that trac control I would've slid right into the cars sitting at the traffic light! It takes some getting used too, but the system works great. If you try and make it slide on purpose you will see how it straightens you out. A little practice will help you become comfortable with it.

 

[brianhuntRVA]

I just drove around my neighborhood in 6-8 inches of powdery snow without it locked. First time driving it in the snow. I must say I am impressed with the 4runners abilities. At no point did it even seem like it was struggling.

 

[Sporin]

You want to lock it drudging through deep snow. Otherwise just keep it unlocked.

Yeah, the only time I lock it is if I'm in a really bad spot and I know I need to keep all 4 wheels spinning (or I'm just exercising the linkage).

I've found the TC to be very good in almost every condition though.

 

[JB.]

How do you determine when....engage center diff lock? I'd prefer not to find out I need it after I wind up in a ditch

Locking it only gives you more traction for pulling -- not stopping or turning -- so the idea of winding up in a ditch because you didn't lock it is a false concern.

You might be more likely to wind up in a ditch with it locked due to carrying too much speed from over-confidence or being unfamiliar with the handling (understeer).

Just use it on the rare occasions you need it.

Some reading if you're interested.

http://www.toyota-4runner.org/4th-g...pavement-center-diff-lock-vsc-off-switch.html