Toyota 4WD systems explained

bp3959

Put a voltmeter on the connections at the horn and have someone inside hitting the horn, if you get about 12v your horn needs to be replaced, which isn't likely as you have two horns. Could also be the horn contacts in the steering wheel, only way to diagnose this is to get a wiring diagram and check the wires leaving the steering wheel. In addition to a horn fuse, you should also have a horn relay, this is a likely suspect as the panic probably uses a seperate relay.

bp3959

Another fun use for 4lo is ripping stumps, shrubs and small trees out of the ground, I volunteer my truck everytime someone needs this done. Keep in mind that if you do this, use a strong tow strap and not a chain, because if the chain snaps, it'll recoil right back at you.

stever

Seems like straps break now and then too, and would also be hazardous. I thought (briefly) about using my Outback to string a short section of pasture fence but quickly came to my senses (dire warnings on the net helped too <g>).

My first car was a CJ-5 with optional locking hubs. Never got it stuck, so obviously I wasn't off-roading hard enough.

Quest4suv, try the Sienna Owners: Problems & Solutions discussion or the Got a Quick, Technical Question? one.

Bp3959, the Subaru Crew here is very active and can help you better than me. But if it's a used one being sought, tell your friend to stop older couples driving one in the grocery parking lot and ask them if they are ready to upgrade to a new one and tell them that you're interested in their old one. Several of us got ours like that (my '97 cream puff had ~34,000 miles on it when I got 15 months ago).

Ok, back to playing in the mud with Toyota's!

Steve, Host

yobow1

Thanks for following up, toyboxx. It looks like my initial question stirred quite an unintentional flurry of responses. But, anyway I haven't done much off roading, so I probably really don't need the 4WD. It was more from a safety issue, which as you point out, the 4Runner has comparable systems. I think I'll probably stick with the 2WD version. My thanks to all who tried to explain.

toyboxx

With the 2wd you still get the VSC and I think some kind of system that helps prevent rear wheel slippage under low traction situations. (double check on that second part or maybe someone who has the 2wd can comment)

So even in 2wd it is a safe and capable vehicle.

bp3959

On the 2000 Sienna, there is a horn fuse in the engine compartment.

bp3959

>>Bp3959, the Subaru Crew here is very active and can help you better
>>than me. But if it's a used one being sought, tell your friend to
>>stop older couples driving one in the grocery parking lot and ask
>>them if they are ready to upgrade to a new one and tell them that
>>you're interested in their old one. Several of us got ours like that
>>(my '97 cream puff had ~34,000 miles on it when I got 15 months ago)
>>.

Interesting way to buy a vehicle. That's actually a pretty good idea as this we be benificial to both sides. They'd end up getting more than trade value, and you get to buy it without the dealer markup.

bp3959

I was actually surprised at how well VSC and TRAC work. Sometimes the TRAC can throttle the engine when you really don't want it, like pulling out into fast moving traffic but I think Toyota has made adjustments to newer systems so they are not so sensitive.

hank14

Once again, ABS is not disabled in my 99 Landcruiser, even with the center differential locked. It is only disabled when the rear differential is electronically locked, which can only be done in 4Lo. I don't know why, I don't know how. I only know that's the way it is, and it came that way from the factory. I can tell it works when in 4Lo, creeping down a rocky hill without the rear diff locked, the tires don't lock up when the brakes are applied. As a side note, the Landcruiser didn't have traction control or VSC until 2000, which is when they quit offering locking differentials. This may be the last year you could buy a Full Time 4WD vehicle with 3 open diffs, without power transfering aides like wwest refers to.

stet

I posted this question back in June but received no response. From reading past posts, there's obviously considerable expertise on this board. Could you please direct some of that expertise my way???

I have a '99 fwd Tacoma with standard transmission and full-time hubs. Toyota says that no Tacoma can be towed 4 wheels down. Sometimes a manufacturer will make these decisions for legal, not mechanical reasons. Can anyone give me a mechanical reason why I can't tow it behind an RV? If I were to do so, what transmission/transfer case configuration would be best (i.e. both in neutral)? I do not want to install a driveline disconnect like Remco sells.

toyboxx

TRAC, traction control that is what I was thinking the 2wd had I just couldn't remember what it was called since I don't have that feature (I have 4wd)

bp3959

I'm not sure what the answer to your question is, but I'll do some asking around this weekend and see if I can dig up anything for you.

nedzel

On my 2003 4Runner, there is a switch on the dash that says 4WD hi, 4WD lo. Another switch locks the center diff. It also has traction control and a rather over-active spin control. Unfortunately, it doesn't have a locking rear diff, but given the off-roading that I do, that really isn't a big issue for me (other than the "cool" factor).

bp3959

Same exact setup as my Sequoia. I'm curious though, did they give you a button to disable traction control and VSC? On mine I have to manually disable it by disconnecting the brake fluid level sensor.

bp3959

Stet, after some searching I found a pretty good bit of information about towing with 4 wheels down, hope it helps.

http://4wheeldrive.about.com/cs/towing4wheelsdown/a/aa070601a.htm

pschreck

On the 2001 Sequoia you can turn off the VSC with a dash button. The dethrottling portion of ActiveTRAC is disabled while in 4WD, however, if you have VSC on it will dethrottle if VSC senses sideways movement.

bp3959

Yea, but if I go out in the mud for about 45 minutes I'd hate to have my brakes going nuts the whole time. After a few seconds of using traction control it starts beeping and will disengage itself for a short time, and keep doing this over and over again.

wwest

About 45 to be more exacting.

VSC/BA/Trac all rely on the ABS pumpmotor to continuously replenish the brake pressure. This motor is NOT rated for continuous duty and is disabled for a cool down period after about 45 seconds of continuous use.

ABS & locked center diff'l.....

During braking the front brakes do about 80% of the work. That means, typically, that the front wheels will turn a lot slower that the rear. Except, of course, if the front and rear are locked together via the driveline.

Obviously ABS cannot operate at the front independent of the rear in those circumstances. That's the reason the Chrysler T&C AWD system has an over-running clutch in the rear driveline.

Most SUVs disable ABS becuase of this, some actually disengage the locking mechanism instead.

pschreck

Sorry, I didn't realize you had a '01. I should have known, you have metioned it in previous posts.

hank14

Refresh my memory, but how is it that if all 4 wheels are making contact with the ground and you have ABS preventing wheel lockup during braking, the front wheels can be spinning "a lot slower" than the rear?

For the third time, my Landcruiser (and I imagine 80 series cruisers with ABS as well) does not disengage the locked center diff or disable ABS when driving in part time 4WD with the center differential locked. It does not seem to cause a problem, either. Isn't ABS the exact or equivalent opposite of TRAC (traction control), by releasing the brakes instead of applying them? Isn't TRAC designed for 4WD? What's the difference?

bp3959

Good info, I knew there was a reason, just wasn't sure of the specifics. Thanks.

bp3959

TRAC disengages when the center is locked.

stever

"Also, there is the matter of all-wheel drive, which the auto industry, for marketing purposes, deliberately confuses with four-wheel drive. The two are not one and the same."

Washington Post

Steve, Host

brian211

Was thinking about a 4x4. After reading the posts in here the last few days, maybe a good pair a snow shoes should be best. Was looking at all the 4x4 or awds on the market. Jeep, mitsu, subarus etc. While looking at the 4runner and deciding on v6, part time 4x4 or v8 full time, decided to read this thread for recommendations. Am in nyc, will not off road, just want safety in snow, with all talk about abs, locking diff, engine speed, and all the rest you talk about, I'm just a joe schmo, what do I need? You got me concerned that in 4wheel drive going up hill the car won't go unless I disconect this or do that, please make it simple or its snow shoes for me. Thanks.

brian211

Also, can I or can I not drive in 4x4 mode on dry or wet pavement or not? If I'm on a side street that's snow covered in 4x4 and come to a main road that's plowed and treated and just wet, do I disengage back to 4x2 or stay in 4x4 without damage? In summer, do I use 4x4 just to keep it lubricated once in a while? Should vehicle have to be towed, do I have to have a flat bed only or can it be towed by regular tow with a wrecker. Also, if I have a flat, is it safe to drive a short distance without damage? Another info in same vain would be appreciated. Maybe an idiot proof awd might be my best bet or just a reg car with snow tires! Thanks.

bp3959

AWD is a decent solution for anyone that wants excellent traction in adverse conditions(snow/rain/gravel) but doesn't want to mess with all the different modes and buttons. If you want the extra safety in a vehicle that doesn't offer AWD, one with either automatic 4wd or a full-time 4wd mode will do, as you can leave the vehicle in these modes all the time and forget the other modes exist.

bp3959

Check your book to see type of 4wd you have.

Full-time 4wd:
  The terms that can indicate this type of 4wd are limited slip center differential, open center diff, or unlocked center diff. Full-time 4wd is more common than part-time 4wd, although alot of vehicles with full-time will also have a part-time mode. In this mode you can drive on dry pavement or slippery conditions.
  A flat tire should not damage your drivetrain going slow for a short while unless you have a clutch-type limited slip(common in 2wd vehicles as well), your rim is another story though. If the vehicle has traction control, a flat tire will probably freak it out pretty good, so it'd be a good idea to disable this if you have a flat.
  If you have 2wd and full-time 4wd, you should drive a few miles in 4wd every 3-4 oil changes.
  Generally you shouldn't drive on a flat tire in any vehicle unless it's an absolute emergency, if you dislike changing tires that much go get a roadside assistance plan

Part-time 4wd: This indicates you have a locked center differential(or transfer case), and your manual will cleary indicate that it's for low traction surfaces only. This should never be used on dry pavement or any other high traction area(unless you are crawling over rocks, but it doesn't sound like that's your goal). Having a flat in snow shouldn't damage your drivetrain, since that tire will just slip around.

AWD: Most vehicles that have AWD will have this as thier only mode. Should not be driven with a flat.

Snow tires or all-terrain tires are a good idea with any AWD, 4wd, or 2wd vehicle in the snow as your drivetrain will only help you go, not stop. All-terrain tires are a better idea than snow tires as they ride better, last alot longer, and do not need to be changed out when winter is over.

Unless your manual explicitly says otherwise, you should assume that a vehicle with any type of 4wd or AWD system should only be towed with a flat bed unless you have an aftermarket driveshaft disconnect installed.

The reason that alot of people prefer a vehicle with both full-time and part-time 4wd modes is that you can use full-time 4wd all the time, and switch to part-time 4wd if you ever get stuck. Part-time 4lo can get you out of alot of situations that AWD and full-time 4wd won't touch(ever been in a ditch, or part-way on a sheet of ice).

When you buy a several thousand dollar vehicle, please take the time to read the manual. At $20 an hour it takes 125 days of work to buy a $20k vehicle, and only a couple hours to make sure you know how to care for it and use it properly. If there is something in there you aren't too sure of, we'll still be here to help out.

brian211

Thanks. Stil the question. V8 or V6? V6 is rwd and can be put in 4x4 mode. V8 is permanently in 4x4. Which is best idiot proof? Are the jeep cherokee or liberty or dodge durango or mitsu montero or gm or ford any better or worse? The less I have to do the more comfortable I am. For the 5 to 10 snow days we have in nyc will be the only times I'd really need 4x4. I would be able to get from home to work and back in 4x4 mode on both wet and snoe covered streets? The flip switch back to rwd for remander of time? The towing thing concerns me. I think a jeep can be towed with a two wheels on ground. Here in nyc I've seen DOT tow trucks move vehicles without owners permision or knowledge. I'm sure they don't care about the damage. Last year they did tree pruning and they took the liberty of towing cars around to accomodate that.

hank14

How many miles do you plan on driving a year? How long do you plan on keeping the vehicle? That can influence your requirements for gas mileage, maintenance, and other issues. I believe the increased costs associated with buying a 4WD are usually recouped at the time of resale. Also, the few times you do need a 4WD, you really need one, IMO. Just remember, 4WD vehicles don't stop any better than 2WD vehicles on snow and ice. That is why lots of them still end up in collisions.

biglatka

Brian211,
I live in the Northeast, in an area that gets a lot of ice and snow. I own a 2004 4Runner V6 with 4WD. The beauty of it is that I can drive it around in 2WD when 4WD is not necessary. This way I save on gas and drive train wear. But if I need 4WD I can turn a switch to 4WD mode (on the fly if necessary) and that's all I have to do. It is then in a full -time 4WD mode that can driven on any type of surface (including dry pavement), and can be left in that 4WD mode indefinitely if I choose to. I also have the ability to lock the center differential, for special low traction situations. Having, as standard equipment, ABS, TRAC, and VSC also helps both handling and especially safety. My feeling is that if you want the best all around 4WD system that is also idiot-proof (if you want it to be) , the 4Runner fits the bill. If all you&#146;re looking for is the ability do drive in snow, on ice and/or wet roads I don't think you'll ever need to lock the center differential anyway. If the roads were that bad, they'd have a ban on driving altogether, we&#146;re not in Montana <grin>. Your other questions were answered throughout this forum. Just use the search facility to find the answers. Hope this helps!

pschreck

If a Subaru is big enough for you, it's all you need for city driving in the snow. You'll never have to mess with anything. An Outback will go through eight inches of snow with ease and is great in the rain. Drives like a car and has a low center of gravity.

If you need something larger, maybe a Highlander or a Honda Pilot will make you happy.

Stick with the Japenese products. Personally, I wouldn't buy a Cherokee with my hard earned money. They seem to fall apart quickly. Read the Jeep forums.

brian211

So you recommend the V6? I'm looking at the limited. After reading these posts I'm thinking its like flying a rocket ship. Traction control, abs, engine throttle. Limited slip. I just want to go from point a to point b. Didn't realize with abs and traction lock you could get stuck anyway and would have to turn it of or disconnect a hose. Please email brian211@tmail.com

curious54

I have a 2004 LC and am about to tow my trailer home for the first time...well...actually im about to TOW for the first time. So, I was just wondering if anyone has towed something with there LC and also looking for some pointers and the "do" and "dont's".

tidester

You might want to look at the Towing tips for SUVs discussion.

tidester, host

wwest

I have a friend who just destroyed a transmission by towing a long distance in OD. He said he knew better but the engine never seemed to struggle so he thought he had enough torque.....

tlcman

towing doos and DONT´s

1. do, connect slip chains,

       i know they work they have saved me from lossing loads before, but
make sure they dont drag, if they do, wrap them once around the tounge of
the trailer, same with you brake and turn signal wires

2. WIDE TURNS, the way you do it is like a semi, stay in the right lane to
make a right turn tunr you signal on, check left lane if clear start to move
to the left then cut right... BUT BEFORE you cut right make sure nobody
has moved his way into you turn space

    Left tunrs are also like you see semi trucks do it, if a double turn lane
use the right lane not the left...

3. your are not going to pass anthing but a turtle on a hill without
>destroying your drive train... So no shifting, our TLC´s know what to do so
just drive it, and remeber, no shifting, get in the right lane select the
PWR switch if you need it, and let people pass you on a hill.

4. before you depart, get jack, emergancy equipment, spares cotter pins
whatever you need.

dont forget water incase you boil over, TLCs rarely do but you never know.

   Check your brake lights and turn signals, not on your car but on the
trailer...

5. Make sure you know how to use your emergancy equipment

6. If travling in the mountains speed limit those posted yellow signs with
the´suggested´ speed for turns ect. but also mind the people behind you if
they are there for a long time find a space to pull off and let them pass.
Road courtesy always makes people happy... well usualy

7. Make sure you are using the right sized ball for the recever on the
trailer, i didnt one time and would have lost my trailer if i had not
attached my safty chains

----------------------

DONT´S

----------------------

1. Shift... its not a manual transmistion... it knows what to do...

2. if going over passes, on the decline try to avoid downshifting, it heats
up a transmision quickly, but also do not ride your breaks, pump decrease
speed let off the brakes and let the cool, then again ect... if you feel
that they are getting too hot (and you will know when, lots of squeaks and
more preassure is needed) then, on a 5 speed auto you can push the shifter
into 4th, while applying the brakes (if you are traveling at less than 75
mph, you must be very carefull when downshifting, in a 5 speed or 4 speed...
because if you are going down hill with a mass behind you with no brakes on
it it can swing out, and if you down shift at a speed to high for that gear,
the SUV will jolt into that gear, you will hear the engine rev high, as it
attempts to slow the mass down, but do not I repeat DO NOT downshit on a
curve. If what i have explaned happens the trailer can swing around
potentialy causeing a rollover... Another thing... : you are going down
hill, you feel it is ok to downshift, so you shift into OD or 4 (on a five
speed) if it does not down shift into that gear withing 2 seconds turn the
OD on or shift back into drive, this is when the car says no... its telling
you that it knows that it is going to fast for that gear, and will not allow
the downshift... now it will down shift, if left in OD off or 4, but only if
the SUV slows down, bt mind you when it does downshift its is not going to
be smooth, that is why you shift back.... ahh i hope you understand all of
that blabber....

3. attempt a U turn unless you have plenty of room. I would suggest taking
your trailer to a large empty parking lot with another friend and practice
backing up and turning... I know it sounds funny and ´back to the basics´
but i did it when i trailered for the first time and it helped me learn...

4.dont Look back all the time to make sure the trailer is there, it is
always following you just watch the road and other cars and you will do fine

Do have fun its a whole nother driving experiance, you will enjoy it!

wwest

Never, NEVER, use OD when towing if you have a lock-up torque converter. Most modern day vehicles do.

wwest

If there were a way to manually lock-up the torque convertor then the transmission could be safely down-shifted to use engine compression braking for slowing on a downhill run.....

With the torque converter locked up there would be no danger of the transmission fluid overheating....

serranot

wwest - why wouldn't I use OD for towing if the transmission has a lockup TC? Please explain. If the TC is locked, there is a mechanical connection and no danger of fluid overheating.

Tom

wwest

Don't forget that the torque converter is really a torque multiplier. Towing UP a hill "unlocked" the level of torque coupled to the tranmission input shaft will vary as a function of need. And yes, it would overheat if overstressed, but that's a circumstance wherein its does exactly what it was designed to do and if it does overheat then the driver is the one at fault.

Oh, without the increased torque, due to the converter AND the higher engine RPM, with it locked towing uphill, or even on the flat, the clutch disks and/or bands might slip and fail.

serranot

Folks - just picked up an '04 LC, and have been perusing these discussions. One question left unanswered--is the center differential in the LC a Torsen or is it just a conventional open diff?

Thanks,
Tom

hank14

According to Edmund's specs, the center differential is a convential, open differential, but it is lockable, making your vehicle the same as a part time 4Wd system when it is locked. Then you have the hi/lo range transfer case as well. Follow the owner's manual guidelines directing when to use each setting. With traction control and VSC, there should be very few instances when you need to lock the center diff, unless you head off-road.

Congratulations on your purchase.

qualitynut

The Lexus GX470 and 4Runner V8 have Torsen, LC & LX470 have open diffs.

OK, guys, since the newer models have Torsen, does that mean its better than open differentials (with traction, stability, etc.)?

wwest

will always be a better solution over an open diff'l.

bp3959

Wwest, I know you know more about it than that, how about some details for us curious readers. What exactly is a torsen diff, is it just a brand name or a certain type?

serranot

A Torsen is a mechanical differential that uses Invex gearing, rather than clutches, to bias torque to the wheel with better traction. While a standard "open" differential will bias torque to the wheel with the least traction, the Torsen gearsets can be configured to apply more torque to the non-spinning wheel.

All you ever wanted to know about the Torsen:

http://www.sonic.net/garyg/zonc/TechnicalInformation/TorsenDiffer- ential.html

Tom

bp3959

Any idea if there is a torsen that can be installed in a sequoia?

2toyotas

The 05 Sequoia will have a torsen center diff. You can probably install one since it is the same transfer case. I would not really worry, I have an 03 Sequoia and an 04 4 runner,and they are both about the same. I doubt the sequoia will give you any problems with traction, and if it did just lock the center diff if it is an 03 or newer.

bp3959

I have the 01 Sequoia, I hate having to go into 4lo*lo to lock the center as there could be a need to rock from drive to reverse with the center locked. I rarely have any traction problems, but a torsen would be nice as I like to play in the mud and snow sometimes, which the Sequoia does great in btw.

hank14

This may have been covered before, but surely there is a way to install a selectable center differential lock switch in your Sequoia, like the Landcruisers have. It might be worth calling the guys at Sleeoffroad or Man-a-fre.