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Thread: Center diff lock question on V8 4Runner

  1. #1

    Center diff lock question on V8 4Runner

    Spent a big chunk trying to understand all the different kinds of traction stuff and I still don't feel like I "totally get it". Please don't try to explain it... it's just too damn confusing. Every time I feel like I understand, I read something else that throws it off. BUT.... I do have a question.

    I have a 2004 V8, so it's full time 4WD. To me, that means I have power going to 2 wheels, one in front and one in back. In this setup, if I get stuck, I take it that the power goes to the wheel w/ the least resistance. I'm guessing this is the same for both the front and rear axles. I'm bringing this up because there have been a couple of times where I felt like I really could use a locked axle (front or rear), and I've been told I have open diffs., which I concur.

    My question is... what the hell is the Center Diff Lock button for? Also, does the center diff lock react any different if I'm in 4Lo or 4Hi? ....because when I used the Center Lock, it sure didn't seem like it helped me get out (but then maybe it did since I didn't try it with the center diff lock off).

    If it's going to take a big ole' explanation, than never mind. It already bothers me that I have to ask this question having had my truck for almost three years.
    Mark<br />KJ6QXG<br />2004 V8 4Runner 4x4, ToyTec Ultimate Lift, Spydertrax, Yakima roof rack, Gibson exhaust, Stubbs Welding Sliders, P275/70R17 BGF A/T K/O

  2. #2

    Re: Center diff lock question on V8 4Runner

    my understanding is you have power going to the the one of the 4 tires with the least amount of traction, because the transfer case is a "open diff" between the front and rear. This is why you can be in 4wheel drive on pavment where I cant.

    locking the transfer case gives you a true 50/50 split of power to the front and rear. now you will have one tire on each end with power.

    How it behaves in 4hi vs 4low...I have no idea. as long as you dont lock it on the street then you should be fine to experiment.


  3. #3

    Re: Center diff lock question on V8 4Runner

    Quote Originally Posted by troyboy162
    my understanding is you have power going to the the one of the 4 tires with the least amount of traction, because the transfer case is a "open diff" between the front and rear. This is why you can be in 4wheel drive on pavment where I cant.

    locking the transfer case gives you a true 50/50 split of power to the front and rear. now you will have one tire on each end with power.

    How it behaves in 4hi vs 4low...I have no idea. as long as you dont lock it on the street then you should be fine to experiment.

    This is my understanding as well. (we have a 96 FJ80 with center diff lock, but we also have the good fortune to have front and rear lockers as well)
    -Chris
    2004 DoubleCab Tacoma PreRunner: 3.4 V6-Auto, DD/Tow Rig
    1997 Lexus LX450: 4.5 I6-Auto, DD
    1984 4Runner: 22R-5 speed, 14 inch bob, 5.29's, lincoln locked rear, lockright front, Armored and Caged by Mossyrocks Fabrication, total disregard for body damage.
    1997 4Runner: GONE
    1996 FZJ80 Land Cruiser: GONE

  4. #4

    Re: Center diff lock question on V8 4Runner

    Quote Originally Posted by troyboy162
    locking the transfer case gives you a true 50/50 split of power to the front and rear. now you will have one tire on each end with power.
    That's what kind of confuses me. If locking my center diff gives me 50/50 between the front and rear, what is it when it's not locked since my V8 is full-time 4WD?

    I guess maybe that's what I'm confused about. What is the "normal" 4WD in the V8 4Runner? I guess I feel like full-time 4WD should mean it already has 50/50 and that center lock SHOULD be what an axle lock should do. Obviously this is not the case.
    Mark<br />KJ6QXG<br />2004 V8 4Runner 4x4, ToyTec Ultimate Lift, Spydertrax, Yakima roof rack, Gibson exhaust, Stubbs Welding Sliders, P275/70R17 BGF A/T K/O

  5. #5

    Re: Center diff lock question on V8 4Runner

    Quote Originally Posted by troyboy162
    my understanding is you have power going to the the one of the 4 tires with the least amount of traction, because the transfer case is a "open diff" between the front and rear. This is why you can be in 4wheel drive on pavment where I cant.

    locking the transfer case gives you a true 50/50 split of power to the front and rear. now you will have one tire on each end with power.

    How it behaves in 4hi vs 4low...I have no idea. as long as you dont lock it on the street then you should be fine to experiment.
    He hit the nail on the head

    When its not locked it like having an open diff, on an axle, the two tires get the power but the minute one tire looses traction it will get more power, so in this case lets say the rear tires loose traction but the front still has good traction, the power will go to the rear and spin the rear tires more
    Avdian (Avy, Avi, Av, Eddie are some nicknames)
    Tess - 97' 4Runner "Project Something Or Another"
    Natascha - 99' GTI 2.0 N/A Auto - SOLD!!
    Swordfish - 05' Camry 2.4 Auto

  6. #6

    Re: Center diff lock question on V8 4Runner

    OK, let me do my best here

    Every day, your 4runner is a type of all wheel drive. what this means is on dry roads, power is going to all 4 wheels, but each diff (front, rear, and center) is equalizing the loads from each wheel and each axle, resulting in normal performance. if for any reason one wheel spins, all power will be transferred to that wheel, resulting in a loss of traction and forward (or reverse) progress.

    when you engage the center diff lock, you are turning your AWD system into a traditional 4 wheel drive system, like the one i have in my 4runner. this center diff lock locks out the center diff, effectively linking the front and rear drive shafts together. if you lose traction on the front axle, all the power going to the front axle will go to the wheel with no traction, BUT, the rear axle will still get the same amount of power.

    similarly, with a locked rear axle for example, power will go to the wheel with least traction, but with a axle diff lock, power will be split equally between the wheels.


    I think this should help you understand how it works: http://auto.howstuffworks.com/differential.htm

    Now, that being said, here is what you REALLY need to know
    Street: High range and center diff unlocked
    Dirt road: high range and center diff locked
    rocks: low range and center diff locked.

    basically toyota added the center diff to allow it to be all wheel drive for the street. they added the locker to still be capable offroad.
    2005 Lexus LX470 - Stock for now...

    1998 Toyota 4Runner SR5 V6 4x4 + a bunch of goodies. Lifted, Locked, Illuminated and Armored. Winner,"Best Offroad Truck" - 2010 Pismo Jamboree. It's been upside down and still drives me to work.

  7. #7

    Re: Center diff lock question on V8 4Runner

    Doesn't the 4Runner use a Torsen center diff? How different is a Torsen diff when compared to an open diff?

    My understanding is that a Torsen center diff will always send power to the both axles, but with varying amount front to back depending on traction. With an open diff, the power goes to the wheel with the least amount of traction, but with a Torsen, some of that power still goes to the wheel with traction, even if the diff is unlocked. Locking the diff will send the power 50/50 front/back.

    Somebody correct me if I'm wrong.
    -Daniel2000 4Runner Sport | V6 | 5spd | 4x4 | Leather | 265/75-16 BFG AT/KO | OBA | BudBuilt front skid

    1990 4Runner SR5 | V6 | Auto | 2wd | 3.90 rear | Cobra CB | 265/65r17 Bridgestone Duelers H/Ts | '08 Tacoma 5 spoke rims | Has an 11:1 crawl ratio! SOLD

  8. #8

    Re: Center diff lock question on V8 4Runner

    Quote Originally Posted by Seanz0rz
    OK, let me do my best here

    Every day, your 4runner is a type of all wheel drive. what this means is on dry roads, power is going to all 4 wheels, but each diff (front, rear, and center) is equalizing the loads from each wheel and each axle, resulting in normal performance. if for any reason one wheel spins, all power will be transferred to that wheel, resulting in a loss of traction and forward (or reverse) progress.

    when you engage the center diff lock, you are turning your AWD system into a traditional 4 wheel drive system, like the one i have in my 4runner. this center diff lock locks out the center diff, effectively linking the front and rear drive shafts together. if you lose traction on the front axle, all the power going to the front axle will go to the wheel with no traction, BUT, the rear axle will still get the same amount of power.

    similarly, with a locked rear axle for example, power will go to the wheel with least traction, but with a axle diff lock, power will be split equally between the wheels.


    I think this should help you understand how it works: http://auto.howstuffworks.com/differential.htm

    Now, that being said, here is what you REALLY need to know
    Street: High range and center diff unlocked
    Dirt road: high range and center diff locked
    rocks: low range and center diff locked.

    basically toyota added the center diff to allow it to be all wheel drive for the street. they added the locker to still be capable offroad.
    Thanks for the link, Sean....I think I finally get it... damn! Part of the reason I was so confused is because I was thinking the "traditional 4WD" is what I thought it had already without the center diff lock engaged. The reason being, if I'm on a DRY surface with good traction, I DON'T CARE if I'm 4WD, because I'm moving. I'm not stuck, so 4 wheel, 3 wheel, 1 wheel.... I'm not stuck, why does it even matter to me? It's when I'm STUCK that I need help, and losing traction on a wheel in the front and one in the back means I'm basically not going anywhere since both sides have a wheel w/ no traction (least resistance).

    Now, I will say it DOES help in dirt conditions (since the "weak" wheel still has measurable traction), but I feel like I'd rather forgo the center diff lock and have a REAL lock instead.

    Hey Daniel, Sean's link explains the Torsen (TORque SENsing) differential pretty good. You're kinda on the right track, but as Sean said, if one of the front or rear tire is spinning, it splits the power front and back. The problem is if there's one spin in the front and one spin in the back that causes us to get stuck. This can happen in snow, mud, and really soft sand.

    Basically, I need to get a real locker, unless I'm only going to stay on dry, TRACTION surfaces... and that's not always easy to predict when you go exploring.
    Mark<br />KJ6QXG<br />2004 V8 4Runner 4x4, ToyTec Ultimate Lift, Spydertrax, Yakima roof rack, Gibson exhaust, Stubbs Welding Sliders, P275/70R17 BGF A/T K/O

  9. #9

    Re: Center diff lock question on V8 4Runner

    I went alot of places with unlocked axles. I still do. when you lock your center diff, you are like my truck in 4wd. very capable! alot of that capability though is skill and more importantly practice. Come with us up to big bear next time and we will put you through your paces.

    even better, come up to hungry valley for the toys for tots toy drive and we can play on the practice ramp!
    2005 Lexus LX470 - Stock for now...

    1998 Toyota 4Runner SR5 V6 4x4 + a bunch of goodies. Lifted, Locked, Illuminated and Armored. Winner,"Best Offroad Truck" - 2010 Pismo Jamboree. It's been upside down and still drives me to work.

  10. #10

    Re: Center diff lock question on V8 4Runner

    the center diff locks basically forces the power to be distributed 50% to the front and 50% to the back. now this doesn't mean you're getting 25% to the front right, 25% to the front left, 25% to the rear right and 25% to the rear left. to get 25% on all four corners you need a front and rear locker. which ensures that you're getting 25% on each tire.

    the awd system we have is really a complex work of art using the "well sort of the latest" technology out there. (obviously this is at the time of production). it basically utilizes a system of checks and balances with the way you drive and the road condition to determine the best power balance to distribute the power down to the wheels. This means that the power may be 30%/70% (front/rear) or even the opposite of 70% front and 30% rear. It's calculating every chance it can and distributing the power accordingly so you the driver gets the best performance out of the vehicle.

    for practical applications I just lock my center once I'm on dirt. That way I know it's 50/50 and then from there I decide if I need to lock anything else beyond that.
    Lance
    TLCA Member

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