domstriker
New member
So you're saying that with a center diff lock, my righ and left wheels are locked?
This is contrary to what I thought but I'm a newb.
So explain elockers to me
- Thread starter domstriker
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So you're saying that with a center diff lock, my righ and left wheels are locked?
This is contrary to what I thought but I'm a newb.
JohnsD90
New member
Locking the center diff sends equal power to the front and rear axles, and it allows slippage. NOT TO THE RIGHT AND LEFT WHEELS.
domstriker
New member
so you're saying right and left wheels are locked together with center diff lock?
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domstriker
New member
No. That's the flux capacitor. You have one of those on your runner too? Only problem with mine is that I can never find enough road to hit 88 mph.
domstriker
New member
Holy crap. I just read through your mod list and you actually do have one. That's badass. I was just posing.
OK-resume diff lock discussion.
Martinjmpr
New member
No.
Rear diff lock and center diff lock are apples and oranges.
Here's why:
First off, I'm sure you understand the purpose of the differentials in your axles, right? When you go around, let's say, a left hand turn, your outer (right) wheel has to go faster and farther, while your inside (left) wheel goes slower and a shorter distance. The differential is what allows the outer wheel to go faster and the inner wheel to go slower.
If you didn't have a differential there at all, you'd have a locked axle - the left and right would get the same amount of power and would always turn at the same speed.
The problem with open differentials is that if you lift one wheel off the ground, it will take all the power, and it will spin in the air while the tire with traction remains motionless on the ground.
What a rear locker does, then, is that it temporarily disables the rear differential and allows both wheels to turn at the same speed all the time. Obviously, this is not something you want to do on the streets as it could cause damage to your tires and drivetrain, but off road when you are bouncing through the rocks it can be a lifesaver.
The center differential is different.
On a "conventional" 4wd vehicle, you cannot run the vehicle in 4wd on dry, hard surfaced roads. The reason for this is that the transfer case splits power 50/50 to the front and rear driveshafts. The problem with that is that on most vehicles, when turning a curve, the front axle actually travels a bit farther than the rear axle. So, with 50% of the power going to the front axle and 50 to the rear, both axles (and the rest of the drivetrain) get stressed out because the front axle has too little torque and the rear axle has too much. That is why conventional 4wd vehicles all have stickers or plates that warn you not to drive in 4wd on a dry, hard surfaced road.
Now, on a wet, slippery road, or off-road, this isn't a concern because the slipping caused by the lack of traction will relieve the drivetrain of any stress. Off-road, if you lift your wheels (pretty common off road) this will also "unload" the stressed out drivetrain, which is why you can run in 4wd all day if you are 'wheeling.
Years ago, manufacturers saw the desirability of running in 4wd on the streets, so they came up with a system where they put a differential (like the one you have in your front and rear axles) into the transfer case. The center differential allows the front and rear driveshafts to turn at slightly different speeds to allow for the longer path of the front axle. These vehicles are full-time 4wd or are sometimes called AWD.
The problem with the center diff is that, like the open diff on the axle, it wants to send all the power to the driveshaft that is spinning the most, so if you lift one front tire off the ground and it takes all the power from the front axle, the center differential will want to take all the power, too, and leave the rear driveshaft (and rear axle) with no power. So, almost every manufacturer who makes a full-time 4wd vehicle equips it with a center differential lock. The center diff lock disables the center differential and the vehicle, at that point, acts just like a conventional 4wd vehicle with 50% of the power going to the front driveshaft and 50 to the rear. Of course, this is for off-road/low traction surfaces only.
On the 4runners, All 4runner through 1998 had conventional 4wd. No center diff lock.
The rear E-locker became available in 1996 with the 3rd gen 4runner. The E-locker is on most Limiteds and some SR5s (my SR5 has one.) E locker was available through the 2000 model year.
From 1999 through 2000, standard models and SR5s had conventional 4wd with no center diff lock. Limiteds (most of them anyway) had both the rear E-locker and the center differential (which is one reason why the 99 - 2000 Limiteds are among the most desirable of 3rd gen 4runners.)
Starting in 2001, all 4runners got the center differential, but the E-locker was no longer an option. They also got a VSC (Vehicle Stability Control) system.
Put more simply: The center differential gives more on-road capability (by allowing you to drive your vehicle in 4wd on the streets) while the rear diff E-locker gives better off-road performance by allowing you to lock your rear differential when in 4wd-lo range.
Martinjmpr
New member
Absolutely, but the front diff lock has to be added on aftermarket - it was never an option from Toyota. In fact, there aren't too many vehicles that ever offered front diff locks. I think some of the FZJ-80 Land Cruisers had front E-lockers, and I know the Jeep Rubicon has them. I think the Dodge Power Wagon might also have a front E-locker.
For a front locker, most 4runner/Tacoma owners use an ARB Air Locker. The ARB uses compressed air to lock and unlock the differential.
As for the Center Diff/Rear Diff lock combo, the only way to get that from the factory is in a 1999 - 2000 Limited.
On your '01, you already have the center diff. If you wanted to add front and rear lockers you could either swap in an e-locker from a 96-2000 4runner, or you could put in ARB front and rear lockers.
Really, front lockers are for hardcore rock crawlers, IMO. If you are a casual 4 wheeler you will probably never need a front locker. They can also make the vehicles somewhat harder to drive.
FINAL NOTE: I've never heard of anybody "adding" a center differential, though I suppose it could be done if money was no object. For example, on my 99 SR5 I don't have the center diff. If I really wanted one, I guess I could swap out a T-case from a 99 - 2000 Limited or from an 01-02 4runner of any kind. I don't know how difficult (read: Expensive) that would be but it wouldn't be cheap. So, really, if I wanted a center differential that badly, my best bet would be to sell my 4runner and buy one that already has the center diff.
OTOH, adding a rear or front locker is pretty common, cost is anywhere between $500 and $1500 depending on what parts you use and how much of it you do yourself.
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domstriker
New member
Thanks Martin.
This is what I originally thought. Although I understood the purpose of differentials and lockers, your post clears up the confusion regarding the center diff.
I thought JohnsD was saying that there was slippage between the front and rear diff only and that the right and left wheels were locked. This is why I asked if he meant right and left instead of front and rear.
Thanks again.
This is what I originally thought. Although I understood the purpose of differentials and lockers, your post clears up the confusion regarding the center diff.
I thought JohnsD was saying that there was slippage between the front and rear diff only and that the right and left wheels were locked. This is why I asked if he meant right and left instead of front and rear.
Thanks again.
nor cal boy
New member
also, their is the difference betwen selectible(arb, oem elocker), and automatic lockers(detroit, powertrax). selectible you well.. select weather you want open or locked differental. automatic lockers lock when you are accelerating and unlock when you are coasting, alowing you to coast around turns(ie, you dont have to stop and press a switch to engage). however automatics change how you drive the vehicle and can be kinda noisy and harsh.
if you drive on road alo, but still want lockers, selectible is what you want. for mostly off road vehicle, automatic is nice
if you drive on road alo, but still want lockers, selectible is what you want. for mostly off road vehicle, automatic is nice
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