Locking the Diff...
- Thread starter E34M5
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E34M5 said:
I wouldn't recommend locking the center diff even on a snowy highway. IMO you would be better off letting the Torsen work it's magic. Think of it as having the center diff lociked into a range, with a 40/60 front/rear as the default split, but automatically ranging from a 30/70 split to a 53/47 split depending on slippage.
Also, locking the center diff turns off the VSC system, which is something that could save your ass on a snowy highway. Toyota originally assumed (I assume
) that you would only want to turn off VSC when you lock the center diff during off-roading. Benefit of that is that it stops the computer from cutting your throttle. Of course now that they put the seperate VSC off button (starting in '08 I think??) you can decide for yourself.Here is the way I look at it and correct me if Im wrong. 4HI, diff unlocked = Full Time 4wd (Awd, open diff) and can be driven all the time. 4HI diff locked = Part Time 4wd and only to be used in snow covered roads, mud, offroading.
Having owned about 13 Jeeps Im very used to 4wd but new to Yota system. Ive lived in North Dakota and Iceland and very used to driving in snowy conditions. On a Jeep without a Full Time (AWD) option you have the part time system (locked) and I always used it in snow. Patchy snow covered roads will be driven unlocked on the 4Runner. Deep snow will be locked.
Having owned about 13 Jeeps Im very used to 4wd but new to Yota system. Ive lived in North Dakota and Iceland and very used to driving in snowy conditions. On a Jeep without a Full Time (AWD) option you have the part time system (locked) and I always used it in snow. Patchy snow covered roads will be driven unlocked on the 4Runner. Deep snow will be locked.
Kmvreter
New member
There's a thread on here somewhere about snow driving technique. Don't mean to hijack but this is about the diff lock.
This sums it up for how I use it during "a shit storm Canadian winter?? I am talking snow covered pavement and highway..." Snow driving is all about keeping forward momentum. All depends on how deep it gets. I've only locked the diff when there is a chance I'll lose momentum, like going slow with snow up to the running boards (i.e. down an unplowed backroad, highway or in a subdivision.)
ExJeeper said:
This sums it up for how I use it during "a shit storm Canadian winter?? I am talking snow covered pavement and highway..." Snow driving is all about keeping forward momentum. All depends on how deep it gets. I've only locked the diff when there is a chance I'll lose momentum, like going slow with snow up to the running boards (i.e. down an unplowed backroad, highway or in a subdivision.)
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jlmilligan
Member
There is a BIG difference between locking your rear differential and your center diff. There should be now ill effects with the center diff locked if you stay under 65 or so. Reason I say that, is if your VSC comes on then you are in 4wd. Just at different ratios. It will however probably hurt gas mileage. Driving around in 4wd (without front or rear lockers) has never done any permanent damage that I know of. In normal 4wd, no 2 tires are locked to the same rotational speed. Now, If you are talking the rear locker, then you can destroy your rear end and tires relatively quickly. When you turn, your outside wheel will spin faster than your inside wheel. If it is locked then your outside or inside wheel will "skip and jump" to keep up with the opposite tire. Causing wear on your rubbers and major stress on your diff.
Moral of the story,
Center locked is good in most slippery conditions
rear locked is great on loose dirt and mud, VERY VERY bad on pavement.
I personally drive between maine and connecticut once a month rain or shine. I have driven in the slush and muck left by tractor trailor trucks. I feel much better with the center locked and VSC off when the roads get real messy. I have tried both, those 6 inch lips of slush won't throw you around as much in 4wd.
Moral of the story,
Center locked is good in most slippery conditions
rear locked is great on loose dirt and mud, VERY VERY bad on pavement.
I personally drive between maine and connecticut once a month rain or shine. I have driven in the slush and muck left by tractor trailor trucks. I feel much better with the center locked and VSC off when the roads get real messy. I have tried both, those 6 inch lips of slush won't throw you around as much in 4wd.
CJ3Flyr
Super Moderator
GatorGreg said:I wouldn't recommend locking the center diff even on a snowy highway. IMO you would be better off letting the Torsen work it's magic. Think of it as having the center diff lociked into a range, with a 40/60 front/rear as the default split, but automatically ranging from a 30/70 split to a 53/47 split depending on slippage.
Also, locking the center diff turns off the VSC system, which is something that could save your ass on a snowy highway. Toyota originally assumed (I assume
:iagree:
The only bad thing about center diff open in the snow is pulling out from a parking lot. Leave yourself plenty of room. The VSC may cut the engine output. In deep snow ideally you'd lock when max 0-30 acceleration was required and then unlock to drive. The reason you want unlock is as Greg said, the VSC is a huge help and may save your butt. The bad part of VSC is it can screw you pulling out of an intersection/side road/parking lot; anything that requires a "sprint" up to speed.
If you don't have a VSC off switch and wish you had one for winter driving check out the link in my sig.
:cheers:
:cheers:
Rowan611
New member
So if I understand what's been said so far it's ok to lock the center diff in 4hi on really snowy roads. However, won't the fulltime 4wheel drive be good enough to go through almost any situation while driving on paved roads? I would imagine not having VSC on snow covered paved roads may be worse than loosing momentum. I need to search for that thread about driving in snow.
jlmilligan
Member
I think I may do the mod. I do agree with Chris and Greg, I just feel better when the slush is a couple of inches deep with 4wd engaged. Does the auto 4wd (V8) still engaged with the VSC off?
Thai
Elite Member
jlmilligan said:
I am not sure if i agree with above...do you have axle lockers? 4th gen 4runners (except 2009 4runner Trail Edition) do NOT come with axle lockers.
Driving around with center diff lock is something that i would NOT recommend, unless you're off-roading. I would trust VSC over an average person's driving skills. If you are in snow all the time on highway AND have good snow driving skills, then locking center diff is OK. However, if you hit dry land and turn (while center diff LOCKED), then you risk damaging the center differential. Otherwise, i would leave center diff UNlock and let VSC/TRAC do it's thing.
Technically speaking, i think that you can drive STRAIGHT at any speed with the center diff locked.
The reason why locking the center diff is helpful is when you're in deep snow (and while off-roading), there is a chance that one of the axle (front or rear axle) may lose traction completely. If both tires on one axle loses traction, then the Torsen center diff (UNlock) will not work properly...it will send all torque to the axle with the LEAST traction...a rare situation. This is where locking the center diff is helpful...locking center diff assures that 50% of torque goes to each axle all the time. (In addition, while off-roading, it is good to lock in the 50/50 fixed ratio rather than let the Torsen transfer torque back and forth...which may destroy momentum while off-roading.)
CJ3Flyr
Super Moderator
Thai said:
I thought that was the cool thing about T-3. I understood that even with no resistance on one end the other would still get power. What am I missing? I know earlier versions required some resistance on the slipping side/end. http://www.torsen.com/files/Torsen T-3 Technical Sheet.pdfOf course this means I am going to have to put the floor jack under my back axle and drive up my driveway, or at least try
And yes I know, to be fair I must unplug at the master cylinder to defeat ATRAC and VSC. That brings up the point that the ATRAC would force some power forward or backwards based on the ATRAC slowing the wheels on the spinning axle, right?:cheers:
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