I have a stock 2000 4Runner 4WD,3.4L engine, shift on the fly 4WD(not limited edition). My question relates to how many wheels are actually drive wheels when in 4WD. I know this sounds self explanatory when one mentions 4WD, but I need to ask the question. If I engage the 4WD....do all 4 wheels actually drive the vehicle? My previous car was a 2WD (non-4 WD) but only one wheel was actually driving the car when going forward, and the opposite wheel would drive when in reverse...so actually only one wheel was a drive wheel at a time. IS this the case with my 4Runner except its one rear wheel wheel and one front wheel that drive the vehicle when in 4WD...or do all 4 wheels drive the car at the same time? I was told by a Jeep salesman that 4WD really only engages 2 wheels at a time in the 4Runner as opposed to all 4 wheels in the AWD Jeep. would love to set him straight. Sincerely Bruce

Read up on this

http://auto.howstuffworks.com/differential.htm



The only time ALL wheels on an axle will turn is if you have some sort of traction aiding device, like a locker or LSD.

The only jeep that jeep currently markets where all 4 wheels spin would be the wrangler Rubicon(when both the front and rear differentials are locked) to my knowledge. In an "awd" jeep depending on the model you are most likely looking at less ground clearance and less traction then in your 4 runner. If you were to upgrade to lockers in the front and rear in your 4 runner then you would be unstoppable! When you are in 4wd in your 4 runner you are getting power to all 4 but the wheel in the front and the back that has the least traction will spin. DonÆt let some salesman at the stealership jerk you around, he is just desperate for some commission.

-rbrach

ahmen to rbrach...listen to him, he is wise....dont ever take a stealership's car salesman's word for pretty much anything, they just want to sell you a car, thats it, and they'll do anything, and SAY anything to get you into the car that THEY want to sell you....

this forum is pretty good, i've found lots of answers while lurking here for a while. this thread kind of relates to a question i've been thinking about. i have a '02 4 runner 4wd with the standard locking center differential. i dont have any other mods (yet). should i just automatically lock the center dif when i'm offroad, or is there any benefit to leaving it unlocked on the trails?

From my experience there is a benefit to keeping it locked on washboard type surfaces..

The washboard patterns tend to make the rear axle bounce up and down hard, and the more power you put on it, it can get right down right violent.

I find that with it in 4x4 and locked center diff with the front wheels helping with the pulling load, the axles don't tend to bounce nearly as bad when pulling under load on washboard surfaces.

Of course airing down helps greatly too.

Actually the salesman may have been talking about the electronic traction aid on the new Jeep (Grand-?) Cherokee. It's kinda like what MB has on their suv. Something based off the ABS system that pumps the brake on the wheel thats spinning sending power to the ones that aren't. Supposed to work very well.

The new 4Runner has traction control too. All 4x4's will drive all 4 until a wheel loses traction. Then the net traction on an axle is the two times the traction of the wheel with the least. Traction control automatically brakes the wheel with less traction to redirect torque to the wheel with traction. A locking differential can redirect 100% of the torque so that a the wheel with the traction gets all of it. Traction control can't redirect 100% but does a pretty good job.

4Runners with the electric locking differential should only engage it when you lose (or will lose) traction. Leaving it engaged all the time is harder on the drivetrain, tires and axle seals not to mention increasing turning radius. Most times the locker is only needed for brief periods.

Though lockers are a great thing. They are not nearly as good as having 4WD. A TRD locked Tacoma Prerunner (2WD)doesn't stand a chance of keeping up with a open differential 4WD Tacoma. Having both the locker and 4WD is, of course, better. Having a second locker up front makes obstacles even easier.

The Jeep salesman obviously knows nothing about Toyotas which is why he is selling Jeeps.

I think he is talking about the center diff lock, Aka AWD/4WD, not the rear diff.

yeah, i was talking about locking the center dif, which controls the power distribution to the front and rear wheels. my 4runner is stock so i dont have a locking dif on the front or rear.