What situations do you lock you center diff?

[CAN-03runner]

I am looking at it as a whole. If you could turn everything off and lock the center diff, I think it would be a valuable tool, but since it only turns off VSC I think it is a joke. Reason being is that even though it will lock in the power distribution, it doesn't help with abs and traction control kick in and start applying the brakes when you don't need it. I almost hit a curb the other day in the snow because when making a U turn I started to slide. Without the controls I would normally just stepped on the gas to kick it around instead I got a bunch of clicking and beeps while I headed straight for it. Luckily I stopped in time, but back to the point being that the center diff lock was useless in that situation.

My VSC almost never kicks in, except when I'm trying to be Mario Andretti and taking a corner way too fast, usually on purpose, or when doing stuff like quick turns or "uturns" where I probably should have waited a little longer for a safer time to do it.

You not trying to Ken Block that Uturn now were you?? Leave yourself enough time to make a manouvre instead of rushing it, trying to beat on coming traffic and the "scary" situations are avoided.

How about your tires. You were using winter tires, on the winter ice and snow conditions aren't you?, i'm sure you are. The type of tires make a huge difference.

I don't know how ABS negated your ability to drive out of the curve.
And without the traction control you'd just spin in the same spot. Your probably going faster with traction control on, than with it off tires spinning and going nowhere very fast.

I kinda like the VSC. You need to practice for lack of better words. Keep having it activate on curves and safe streets or pempty parking lot to get used to the clicks and beeps, and what causes it to kick in. Something that probably doesn't help the situation is the reflex action of taking your foot off the gas and hitting the brake. You need to see the difference of what happens when you keep some gas input, vs just doing nothing or slamming on the brake.

The truck is braking for you with VSC. You can help by braking too. But sometimes you could just keep your foot on the gas, just a little, the truck will brake and cut power as needed, but it needs gas input to turn the wheels and for trac/atrac to pull you in the direction of your steering. If you don't do that, you just keep sliding into the curb. Try it. It can be a lot of fun too.

I will admit that the Toyota VSC is not perfection. Either it is the programing, or because the truck is so heavy, or tall, or large tire size, I don't know. But the DSC on BMWs is awsome. The practically invented it. You probably will hate it though until it saves your life....in fact after seat belts VSC/DSC systems save the most lives.

On my BMW it pretty much can stop the car dead in its tracks. I don't know how it does it, but you can come down from a good speed, turn a corner on ice, and it just starts to slide to the side and it stops you, you could come to a complete dead stop and sets you straight and keeps you in your lane. It even has control to the steering. How's that for invasive.

If you don't like VSC you will poop your pants in a BMW with DSC activated. Turn it completely off though, and the car is useless on ice. It will let you red line all day and you would have advanced 3 inches while you make a nice slipery ice sheen under your tires.

The traction control on the other hand is lack luster compared to trac or atrac. I prefer to have my traction control than no Trac and VSC. If you have a place with ice on the ground, and you can disable trac/vsc, pres the gas and the tires spin, it only feels like you are going some where. Much more control, much more elegant and safer with trac.

Unless you want to be, "that guy", whose spinning an open diff, with one tire spinning like crazy, going no where. I don't, or I'd have bought a 1993 kia sorrento or something.

 

[JB.]

I almost hit a curb the other day in the snow because when making a U turn I started to slide. Without the controls I would normally just stepped on the gas to kick it around instead I got a bunch of clicking and beeps while I headed straight for it. Luckily I stopped in time, but back to the point being that the center diff lock was useless in that situation.

Not following.

If you got beeps the diff wasn't locked. If it wasn't locked, how do you know it was useless?

 

[scottm]

My Land Cruiser has a lot in common with the V8 4R, but the traction control works a lot better, allows me to drive more aggressively. The best part is you can floor it and it goes without beeps or brakes, supposed to be for clearing mud out of the treads.

 

[medicrn]

Not following.

If you got beeps the diff wasn't locked. If it wasn't locked, how do you know it was useless?

My understanding, and experience is that when the diff is locked there is no traction control and u can spin all wheels to Ur hearts content?
I can't get traction control to kick in w center locked/VSC off...
Abs is still on but does engage while I'm on the gas.
No beeps and no breaking or powering down when locked and on the gas.

 

[jimmied]

Think about what a rear differential does. It has an input shaft (the driveshaft) and two output shafts (the halfshafts). It transmits power from the input shaft to the two output shafts, but also allows them to turn at different speeds.

A center differential is basically the same thing, but with different geometry (and without the reduction gears). The center differential has an input shaft from the transmission, and two output shafts -- the front and rear driveshafts. The center differential transmits power from the input shaft to the two output shafts, but also allows then to turn at different speeds.

When you lock the center differential, the front and rear driveshafts turn at the same speed.

When you go around a corner, the path taken by the front of the vehicle is longer than the path taken by the rear of the vehicle. Therefore, the front driveshaft needs to turn faster than the rear driveshaft. If the center diff is locked and you are off road, the tires simply slip. But if the center diff is locked and you are on dry pavement, the tires can't easily slip and that can cause stress on the drivetrain. That is why you should not drive on dry pavement with the center diff locked (or if you do, why you should not go around corners).

As to when I locke the center diff, I fish on the beach every summer. I lock the center diff before I drive onto the beach. I don't normally lock the center diff on a snow covered road unless I'm going up a steep hill or the snow is very deep.

Ok. Thanks. I understand this better now. My wife had a 98 pathfinder years ago and it would definitely bind up at times while in 4wd. I am guessing that was preloaded when switching to that mode. Snow is on ground now so I need to go out and see how this truck handles for the first time in the snow both locked and unlocked.

 

[M1911]

That Pathfinder may have had a part-time 4WD system. Part-time systems are by far the most common. Part-time 4WD systems don't have a center differential. When you put a part-time 4WD vehicle in 4WD, the front and rear driveshafts turn at the same speed. As a result you get binding when going around a corner on dry pavement.

 

[JB.]

My understanding, and experience is that when the diff is locked there is no traction control and u can spin all wheels to Ur hearts content?
I can't get traction control to kick in w center locked/VSC off...
Abs is still on but does engage while I'm on the gas.
No beeps and no breaking or powering down when locked and on the gas.

I avoid the term traction control because it hasn't been used consistently by Toyota over time.

In descriptive terms there are two things going on (1) engine suppression, and (2) brake pulsing (in various forms to control different aspects of traction and handling).

With the diff locked, engine suppression and skid control are off. Brake pulsing to control wheel spin is active but you may well never experience it on road due to the capability of the truck in that mode. If you're skeptical it's easy enough to test. Just find a large, plowed snow drift or other impossible traction situation somewhere and give it a go.

 

[ddnww]

The bulk of our trucks never get the center diff engaged or 4-lo activated. We are in the minority of drivers that nit-pick these computer aided traction devices. Most of these trucks never get off the pavement and these computer aided features are for the soccer moms of the world.

getting mine the end of the month, and the center diff will be locking nearly every weekend.. 4lo included. sand, steep rutted dirt and rock hills, and muddingt when it rains.

 

[CNJ Runner]

I only use 4wd in snow or mud. That being said its always locked in those conditions as long as im not on dry roads or when traveling at highway speeds.

 

[erpcayne7]

I'm with you - I've never found the center diff lock to be of much use. Now if I'm planning to get into something hairy, I just unplug the ABS ecu to keep the brakes from applying. keep in mind, most of what i do is in the real loose sand and having those brakes automatically apply and slow me down is what gets me stuck

 

[CAN-03runner]

I'm with you - I've never found the center diff lock to be of much use. Now if I'm planning to get into something hairy, I just unplug the ABS ecu to keep the brakes from applying. keep in mind, most of what i do is in the real loose sand and having those brakes automatically apply and slow me down is what gets me stuck

So what you are saying is that you've tried these same locations with center locked which disables VSC but activates A-trac, and still found it to be better to drive along with no traction control at all.

Why do you feel that? Is it because you are doing more high speed stuff? Is it more of a fun factor for you to spin tires, blitzing and having a blast around the sand and not destination based? Did you get stuck with Atrac or just feel like you can't blitz as much and is just not how you have fun offroad?

I might think that in sand probably being so loose and low traction to start with, you are relying more on momentum to keep propelling you forward. So even if atrac slows a spinning tire another tire might not have that much more traction anyway and so atrac braking slows you down even more, but with no atrac you might have been able to just keep moving to the next traction patch by momentum alone.

Just my speculation. No sand up here. Only rocks and northest goop covering rocks hiding in said goop.

So now, lets say you had lockers on the diffs, instead of atrac trying to emulate LSD/Lockers, would you think they would be beneficial or you still wouldn't use them on your sand runs?

 

[M1911]

When I drive on the beach, the most important thing is lowering tire pressure to 15 psi.

 

[fourwd1]

What situations do you lock you center diff?

When I'm forced to park in a bad neighborhood, I lock everything.

 

[KingPrat]

This one.

 

[M1911]

That looks very similar to my driveway. Thank goodness for the plow guy.

 

[crazeazn]

mmm the V6 has an extra mode right? on mine there is 4Hi and 4Lo only. Tell me if I have this right...

So I'm guessing my options are:
4HI + diff unlocked: daily driving (wet etc)
4HI + diff locked: gravel? uneven roads?
4Lo + diff unlocked: Mud?
4Lo + diff locked: extreme worst case scenario?

 

[JB.]

mmm the V6 has an extra mode right? on mine there is 4Hi and 4Lo only. Tell me if I have this right...

So I'm guessing my options are:
4HI + diff unlocked: daily driving (wet etc)
4HI + diff locked: gravel? uneven roads?
4Lo + diff unlocked: Mud?
4Lo + diff locked: extreme worst case scenario?

Yes, those are your options. In terms of when to use and in descending order of frequency, it would look something like this:

4HI -- Daily driving. Almost never have to change out of this mode
4HI LOCKED -- When you need extra traction and don't mind the steering/handling penalty of the locked center. Naturally, this implies lower speed situations. Rarely used on road.
4Lo LOCKED -- Even lower speed situations than the above. Even more rarely used on road.
4Lo -- Mostly a luxury but can be very nice to have.

 

[erpcayne7]

So what you are saying is that you've tried these same locations with center locked which disables VSC but activates A-trac, and still found it to be better to drive along with no traction control at all.

Why do you feel that? Is it because you are doing more high speed stuff? Is it more of a fun factor for you to spin tires, blitzing and having a blast around the sand and not destination based? Did you get stuck with Atrac or just feel like you can't blitz as much and is just not how you have fun offroad?

I might think that in sand probably being so loose and low traction to start with, you are relying more on momentum to keep propelling you forward. So even if atrac slows a spinning tire another tire might not have that much more traction anyway and so atrac braking slows you down even more, but with no atrac you might have been able to just keep moving to the next traction patch by momentum alone.

Just my speculation. No sand up here. Only rocks and northest goop covering rocks hiding in said goop.

So now, lets say you had lockers on the diffs, instead of atrac trying to emulate LSD/Lockers, would you think they would be beneficial or you still wouldn't use them on your sand runs?

Most of what I do when out in the sand is probably pretty reliant on momentum. It is just for fun and not really destination based, so it goes hand-in-hand with what you said, having the a-trac activate to try to find another wheel with more traction might be an exercise in futility, since there is most likely no better traction option. but if the a-trac applies when i'm out there and starts applying brakes to find better traction it just bogs me down and i get stuck more often than without. now, where i to go somewhere that's more wooded, rocky, and muddy (like canada [or the northwest]) i'd probably have more use for the center diff so that i could send power equally to the front and rear axle. as for having a locking rear diff, i've always wanted to get one - but i'm not as well versed as some of the members on here when it comes to how all the systems interact with each other, but i'm not sure having a locking rear diff wouldn't leave me in the same situation because i would still have a-trac.

 

[Macaque]

I was just reading the VSC/Traction control debate that was going on. I've found that with the center diff locked in 4Hi I can just power through traction control activation. When it's not locked traction control basically takes over the gas pedal and your input doesn't do anything.

 

[Synister]

I was just reading the VSC/Traction control debate that was going on. I've found that with the center diff locked in 4Hi I can just power through traction control activation. When it's not locked traction control basically takes over the gas pedal and your input doesn't do anything.

Better yet, with your 09 SE you can disable the traction aides by pressing and holding the skidding car button. You get all the benefits of the torsen in 4HI unlocked without any traction control intervention. Also works in 2wd and 4lo unlocked.