Toyota 4WD systems explained

brianbm

Cliffy1, it was a darn good set of posts you wrote at the start of this thread. Now I just gotta look around for the right LC.

guti

For those of you with experience in off-roading,a couple of questions:

Do you consider the 03/04 4Runner's skid plates heavy duty? Are they comparable to the Jeep Wrangler's, for example?

Secondly, a Lexus mechanic told me last week that the reason why the GX470 has a manual lever for Hi/Lo shifting is because the transfer's case is extremely "beefy". He didn't know for sure, but speculated that the 4Runner's transfer case is not a tough and, therefore, is operated my motors activated by the in-dash electric switch. I am not sure if that makes sense,although I have noticed that Jeeps and Land Rovers have manual Hi/Lo levers.

What has been your experience in being able to switch from Hi to Lo in the 4Runner? Do you need to be in P or N, or can you do it in gear at low speeds?

Does anyone know if there is a difference between the quality/durability of the GX470's transfer case vs. the 4Runner's?

Thanks.

steenh1

Vodgut and Steelcruiser... thanks for the posts. Clears it up for me. My understanding is that the front locker option went away with IFS. Made the leap that IFS was the reason but maybe that's not the case.

Thanks,

steelcruiser

Steeh1--that's true WRT factory front locker on IFS LC. I believe though that ARB makes a front air locker for the 100 series.

darktiger

Help! I am trying to decide btw a 4X4 4Runner Sport and a 4X2 4 Runner Sport. Here in the state of Texas there are like 4 4X4 v8 Sports editions so my options are limited. Will I know a big diffence between 4X4 and 4X2. It does not really snow down here, it just rains. I tend to drive fast in the rain, but my current vehicle (Jeep Grand Cherokee v8 4X4) I get a sense of security.

nedzel

4WD will not help you corner any better or stop any better than 4x2. Both are more a function of your tires. 4WD will help you accelerate faster in the rain. I have a 2003 4x4 V8. I have not yet seen the traction control light come on while driving in the rain. YMMV.

Since I live in New England, I did not consider the 4x2.

wwest

A few years ago I drove our AWD Chrysler T&C to Tampa and return (Memphis). On the return trip along the coast it literally rained cats and dogs for mile upon mile. I stopped counting the number of vehicles spun out (hydro-planning??) in the median or borrow pit there were so many.

I can't really tell you that the AWD system in the T&C was really any help but I can tell you that I was able to maintain travel at or above the speed limit without even the slightest "wiggle".

And I firmly believe the new 4runner AWD system is amongst the best there is.

Kirstie_H

A major news magazine is looking for an enthusiastic Toyota customer, preferably a buyer (or soon-to-be buyer) of the Sienna, Highlander or Tundra Double Cab. Please provide your daytime contact info and vehicle status to jfallon@edmunds.com no later than Monday, November 3, 2003. Thanks!
Jeannine Fallon
PR Director
Edmunds.com

nedzel

is really a function of tires, not four wheel drive. True hydroplaning occurs at higher speeds when the tire tread is unable to evacuate the water from under the tire. The water builds up and the tire rises up off the pavement, thus reducing grip. Four wheel drive, front wheel drive, or rear wheel drive makes absolutely no difference in such a circumstance.

About the only thing that four wheel drive does better than rear wheel drive in rain is prevent you from getting power-oversteer if you hit the gas too hard in a corner. Of course, if you did hit the gas too hard in a rear wheel drive vehicle and had the back step out, you should be competent enough to counter-steer and gather it up -- a couple hours doing donuts in a snow-covered parking lot does wonders for teaching that skill.

wwest

there are exceptions. You are less likely to have all four wheels lose traction simultaneously due to hydroplanning than 1, 2, or 3.

And don't forget, with (true) AWD the engine torque is being delivered, divided amongst, four contact patches, not just two. Requiring a more serious level of hydroplanning before spinning out of control.

alfster1

Here are links to some videos showing the new model 4Runner off road under varying conditions and showing off some functions, such as DAC.

Enjoy.

http://www.digitalpimp.org/~john/Videos/4Runner%20Stuff/2003%204R- unner/

http://www.digitalpimp.org/~john/Videos/4Runner%20Stuff/Amicalola- %20Falls_Anderson%20Creek%203_03/

nedzel

sorry, but I can't agree with you. Hydroplaning is a function of three things: 1) tires, 2) speed, and 3) depth of water. If you drive too fast for your tires and the depth of water, a wedge of water builds up between the tires and ground and you thus lose contact between the ground and your tires. Therefore, you lose control. Hydroplaning occurs at steady speed and steering inputs while on the highway.

Losing traction while accelerating isn't hydroplaning. Yes, 4WD gives better traction while accelerating. Any decent traction control system and stability control system will reduce the chances of losing control while accelerating and cornering. Neither is likely to do anything much of anything about hydroplaning.

Up here in the Northeast, during snowstorms it seems the most common vehicles to have spun out and lost control are, in fact, SUVs. I suspect it is because the excellent traction during acceleration has prevented the drivers from realizing just how slippery it is. So they just drive too fast for conditions. 4WD can't change the coefficient of friction. If the snow covered road will only support 0.4g sideways acceleration around a corner, 4WD isn't going to let you corner at 0.5g -- you'll still end up off the road. And that is just as true for a rain-slick road as it is for a snow-covered road. 4WD won't let you drive faster around the corner nor will it let you brake faster.

4WD will help you accelerate faster in slippery conditions.

alfster1

Umm, I think you have me confused with someone else's post. I only made mention of the video links to show off some of the 4Runner's attributes. I never made reference to hydroplaning.

*****

However, I agree with your post. Many SUV drivers seem to be over confident in snowy conditions are just are not able to control their vehicles very well. Having a 4wd will almost certainly get an SUV through most snow conditions, but the laws of physics don't change. So, even with 4wd, it may still not be safe to drive in the snow because you have to be on the lookout for other SUV owners who are not experienced in drving in snowy conditions.

nedzel

sorry alfster1, you are correct, I was responding to wwest.

alfster1

doh! :O)

sibiryak

Edmuns gives different prices for 2004 Highlanders v6 w/3rd seat 4WD v. 2004 Highlanders v6 w/3rd seat AWD (the latter is $1000 more). However, when I look on all Toyota sites they only differentiate between 2WD and 4WD, but not the subsets of 4WD (assuming there are any). Are there really 4WD and AWD 2004 Highlanders? If yes, what is the difference? I always thought 4WD was better than AWD, but it does not seem to be the case with Highlander becuase you pay more for AWD than 4WD. I am totally confused!?

meemo87

You are totally confused. Look again at what you think is 4WD. It is actually "FWD", which stands for Front Wheel Drive. Highlander comes with AWD or FWD not 4WD.

low_ball_88

I noticed a grinding sound when I turn off my 4WD while making a U-turn. If anyone knows why and should I be engaging or turning the 4wd off when making turns?

gkatz1

My thought is that engaging or disengaging the 4WD should be done while driving straight ahead. It seems that inbetween the time you push the button and the time it takes to fully engage, the center diff is effectively locked and it will bind.

wwest

Implies that you had/have the 4WD engaged on a high traction surface. You should NEVER do that.

And yes, you should be driving straight ahead when you engage or disengage. You should ALWAYS disengage 4WD immediately upon driving onto a high traction surface.

Unless the diff'l locking doesn't use a "dog-clutch", splined shaft, and absent knowing which always refer to rule #1 above.

pschreck

gkatz is right. Don't engage or disengage the system unless you are driving in a straight line. Once it is engaged however, you may do all the U-turns you want on any type of suface. It's a Full-Time system so you don't have to be concerned with the surface that you are driving on.

gkatz1

I guess we should have asked what kind of vehicle your talking about. I figured you have a 4runner or Sequoia.

wwest

First of all, it was a "grinding" sound...

That certainly implies, at least to me, that we're talking about a true 4WD system (locked center diff'l), not an AWD system (my term for a full time 4WD system, meaning no "locked" center diff'l).

gkatz1

Before 4wd on the Sequoia fully engages it will bind like regular 4WD. Once the center diff is engaged its all set, but you have to be careful.

ddw5

4runner manual specifically warns against engaging 4wd while turning.

coupedncal

Could someone clarify the difference between going to 4Lo in TLC or for that matter any 4WD Toyota and locking the differentials ? I imagine the lockes lock the two wheels on the same axle together so they turn with the same motion but then what does the 4Lo do ?

hank14

Coupedncal-
In my 99 LC, 4LO locks the center differential, distributing power to the front vs rear 50/50, and engages the low gear range. This can also be done in full time 4WD (Hi) by pushing the center diff. lock button, but you stay in high gear. Some TLC's also have a rear and/or front differential lock switch, which solidly locks the left and right axles together. Exactly how this works in other Toyotas depends on the year model and setup. A factory 80 series LC with front, center, and rear differential locks could effectively have 4 or 5 different options for 4 WD, depending on the traveling requirements.
As stated many times, do not lock the differentials unless you are on a low traction surface.

hank14

Has anyone installed an on board ARB compressor on their 100 series TLC? I am thinking about getting one, with the hopes of later adding a front ARB locker. I emailed Man-a-fre to see if the front ARB locker was available for the 99 TLC, but haven't heard back from them yet. Their web site doesn't specify front or rear.

coupedncal

Thanks for the info. Is there any site that explains the 4WD setup in the 80 and 100 series LCs ? I will be looking to get into one in a few months and I am trying to establish as to what type of differential do I really want to get ? Is it true that differentials were optional on all the models or did some have them as standard ? Which year had which option ?

idahodoug

Pre 93 80 series - no F/R lockers
93-97 80 series - optional F/R lockers
98 100 series - optional rear locker only
Can't recall when this rear locker option disappeared in favor of a traction control system.

More info on 80 series - www.sleeoffroad.com

IdahoDoug

bryan28

I think the traction control was used in 2000.
Bryan

idahodoug

Pre 93 80 series - no F/R lockers
93-97 80 series - optional F/R lockers
98 100 series - optional rear locker only
Can't recall when this rear locker option disappeared in favor of a traction control system.

More info on 80 series - www.sleeoffroad.com

IdahoDoug

hank14

98 and 99 100 series both had the rear locker option. Traction control was available in 2000. I called Man-a-fre, and they said my 99 could have a front ARB locker installed, and that the rear electronic locker could be replaced with an air locker, so I assume this is the case with the earlier 80 series models also.

curious54

I have a 2003 TLC with tires that are 305-50-20 (kumho esta). Since the vehicle is all wheel drive, which means that i can partically go anywhere, but does that depend on the type of tires you have. I already went off-roading on these tires..well sorta and they where fine...but imma planning to go skiing in the winter and was wonderingif i needed chains.

rav4guy

My girl friend has a 1999 Rav4 automatic transmission. She said the guy at the used lot told her it was a 4wd, but I can't find anything that labels the car as one or the other. What can we mechanically inspect to be sure?

wwest

The parking area on the mountain gets really icy, damn slippery, in the early afternoon and I have seen many 4WD vehicles needing chains for getting around. 4WD alone isn't really much help if all four wheels are on slippery stuff, ice, well packed snow, etc, chains are required.

low_ball_88

How damaging is it to the 4WD system (Sequoia) if I engaged and disengage the system during a turn. I've only done it twice and now I noticed that when the 4wd system is on, when making turns I could hear a thumping sound coming from the front axle.

pschreck

I'm not the guy to ask. Wish I could help you. I can only imagine that the potential for serious damage is there. It would depend on how aggressive you were in making the turn.

I would pose that question to cliffy or idahodoug.

Good luck.

wwest

If on a slippery surface, gravel, ice, etc, that "thumping", in 4WD while turning, is the sign of a failure or impending failure.

If on a non-slippery surface it's a warning that you're doing something you shouldn't, so STOP.

Never, NEVER, have the vehicle in 4WD in circumstances wherein the wheels cannot slip and thereby relieve the drivetrain stresses arising from a locked diff'l. The only exception is driving straight ahead from one mud puddle to the next mud puddle.

Above does not apply to AWD nor full time 4WD mode.

gkatz1

The Sequoia is designed to operate in full time 4WD on any surface. However, if you try to engage 4WD while turning it will bind and could cause damage. The center differential does not immediately do its job until 4WD is fully engaged, which often does not occur immediately. Until that little orange light stops blinking then it will bind. If you need 4WD immediately then try this while stopped, hit the 4WD button while in drive and shift into neutral then back to drive. Often this will engage 4WD immediately.

ccco1

Rav4's with 2wd, only drive the front wheels. So, a simple way to check for 4wd is: crawl under the rear of the Rav and look for a rear differential with a drive line running to it from the front.

wwest

I'm sure someone will tell me if I'm wrong...

The Sequoia has two modes in which all four wheels are driven. The first of these, which I prefer to call AWD, does NOT lock ANY diff'l.

This AWD (full-time) mode uses an open center diff'l so that all four wheels are driven when on reasonably good traction surfaces. If any wheel(s) should begin to slip then the brake on that wheel or wheels is moderately applied so that engine torque continues to be apportioned equally, in a rough sense.

In "true" 4WD it is my understanding that the center diff'l is locked and therefore all the cautions and warnings apply.

gkatz1

But, where talking about binding that occurs while going from 2WD to 4WD. Between the time the button is pressed and the system actually engages is when you have to be careful because the center diff doesn't work.

wwest

The statement is literally" bumping while the 4WD is on".

The earlier post was regarding the system in transition, this, #1289, was simply "on".

I take that to mean either there is a failure as a result of earlier incidents or the vehicle is being driven on a high traction surface in a turn. Either of my Jeeps would bust knuckles (Ouch, Damn!)in the latter case.

himcdonough

Great posts in this board. I'm trying to diagnose a frustrating driveline thump in the rear end of my 99 LC w/ 60k miles. It typically occurs as the rear end settles after braking or in any situation where the rear settles from a high position as opposed to the rear squatting under weight or compression from a bump. The local dealer says that it is a function of the slip yoke in the drive line found on LCs and new 4WD 4Runners being packed with too much grease. The grease was drained and the problem went away but quickly returned so I'm unsure that's it. It feels as if slack it being taken up and creating the thump somehow between the transfer case and the rear end. Looking for anybody with similar experiences before another trip to the dealer. Thanks.

idahodoug

I disagree this is caused by too much grease in the slip yoke on the rear shaft. Malarky. Within a hundred yards of driving, the excess grease is pushed out the ends of the splines as normal.

It's most likely to be too little or too infrequent greasing of the rear shaft, but that does not seem to be the case here. You don't mention miles or history on your truck. My second suspicion is that you've not done frequent enough tire rotations and one or more tires are a different circumference. Before getting into any elaborate mechanical issues, consider replacing the tires if they justify it. Otherwise, very exactingly measure each tire in turn and see if you find a circumference difference. Run a tape measure around the center of the tread and record it to the 16th of an inch.

What can happen is the center, rear or front (or all three) diffs end up with the gears coming under a slight amount of pressure as you come to rest. It's held this way until the instant you let off, then the gears gently rotate relative to one another (from 'drive' faces touching to 'coast' faces touching or the opposite) when engine torque moves them.

Anyhow, getting technical here, but measure your tires and also be sure they're all properly inflated.

IdahoDoug

John_1

I own an 03 4Runner, and it has the driveline thump described by himcdonough. It most often occurs when getting underway after stopping, but can also occur just before the vechile comes to a complete stop. Here are some facts:

 - The thump went away after I had the drive shafts lubed by the dealer. It returned in about 4000 miles. I'll have them do it again at the next oil change.

 - The thump will never occur if I shift from drive --> neutral --> drive while stopped.

 - My 4Runner has the adjustable air suspension in the rear. When raising and lowering the vehicle, it sometimes makes a popping sound. I suspect that this is due to the extension/retraction of the driveshaft as the vehile is raised/lowered. This did not happen in the roughly 4000 mile period after I had the drive shafts lubed. Therefore, I believe the 'thump' and the 'pop' have the same root cause.

bryan28

I have a 99 TLC with 60k miles and it has the exact thump you describe. I think I called it a clunk so if you search the postings for clunk you will find several posts on the Toyota Land Cruiser board. My thump also goes away when put in neutral after stopping and doesn't happen at all if I stop slowly/gradually. My Toyota dealer called it normal which pissed me off... I would like to hear of any fix you come across with your research so please keep posting.

I was thinking about getting new shocks as I've heard that the stock ones can go bad at around 60k, depends on driving.

Interesting post by Doug, I will check my tires but they are the same age and the tread looks similar... I would like to get new tires though.

sequoiasoon

Many Sequoia's and Tundra's have the same issue new. What seems to fix it is adding grease in the slip joint on the drive shaft. I had posted in Sequioa problems the "fix" from another website. Part of normal maintenance in manual is to grease the fittings at every oil change. My thump has not returned since.

bryan28

Believe me I have greased the shaft and it still thumps... The curious thing to me is the fact that it doesn't do it if you pop it in neutral, I wonder if the shaft has a worn zone and when you stop it compresses beyond the worn area then when you go it pops back down... I don't know. I would buy a new shaft if I was confidant it would fix it.