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Toyota 4WD systems explained

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Comments

  • anilvanilv Member Posts: 1
    While coasting downhill (foot off the accelerator) on a paved road with LOTS of potholes, the front control lever jumped into the N position by itself. The car was moving at about 30-35 mph (fairly steep hill), transmission in D and in 2WD mode. I lost power to the wheels and pulled over to the side. Did not know what happened, had it towed to a dealer who said somebody had pushed the front lever to N (I was alone in car and have never touched the front lever before in my life). He showed me how to move it back. Same thing happened a couple of weeks later on the same road under the same circumstance (coasting at 30-35 mph with foot off accelerator). Now when I am coasting on any road I am able to easily move the front lever to N even when the transmission is in D. Not able to do it when accelerating or with transmission in P. Dealer says it is normal to be able to push the front control lever from H to N while coasting and that the lever jumped to N by itself because of the bad road. To move it back I have to stop, put the transmission shift lever to N and then push the front control lever back to H.
    Is this normal as the dealer insists or is there a problem?
  • wwestwwest Member Posts: 10,706
    Normal..

    If the driveline isn't under "stress", driving or engine braking torque, then the spline type "dog" clutch will slide easily into or out of "gear".
  • ronnronn Member Posts: 398
    Can someone please help a confusing issue for me? If you have a RAV4 Limited 07 or 08, is the 4WD considered AWD on the V6. Is that what on demand is? This is very confusing as I have read that there is an optional AWD on the Limited. I just ordered the 08 V6 Limited which is suppose to have everything on it, so does this include AWD? No where does it read AWD, but mentions ELEC on demand. Any help with this would be appreciate from someone trying to figure this out. I guess I am just stupid with this! LOL
  • lucky_777lucky_777 Member Posts: 205
    Vehicle comes in 2 flavors 4WD or 2WD. Check with your dealer what you're getting.
  • ronnronn Member Posts: 398
    Thanks Lucky....I am getting 4WD, but some have said it is AWD when it's over 25 miles. That was the confusing part that many are asking. Some are saying it is AWD, some are saying it is front wheel drive until it goes into 4WD under 25 mph.
  • cbmortoncbmorton Member Posts: 252
    The RAV4 uses an on-demand AWD system that sends most of the power to the front wheels by default, with a computer deciding how much power should go to the rear at any given time. However, the driver can push a button on the dash to override the computer and "lock" it into a fixed 55/45 F/R torque split at speeds up to 25 mph.
  • ronnronn Member Posts: 398
    Thank you for clearing that up for me. I am looking forward to getting my new RAV4 in about two weeks.
  • wwestwwest Member Posts: 10,706
    First, there is, cannot be, any such thing as FULL-TIME 4WD/4X4 drive mode.

    The term AWD, All Wheel Drive, has been chosen to mean a drive system that somehow has some elasticity in the driveline between the front drive and the rear drive.

    The most viable, most functional on adverse roadbed surfaces, of these (4runner, Honda/Acura SH-AWD) are rear torque biased and with the ability to remove ALL drive torque, leading or lagging (engine compression braking) from the front wheels when or even directional control is threatened.

    Insofar as I can tell the entire Toyota and Lexus FWD based AWD fleet are referred to as AWD for marketing purposes only. Very little real, or no, AWD functionality whatsoever.
  • cbmortoncbmorton Member Posts: 252
    Congratulations - enjoy your new RAV4. I've had my V6 AWD for a bit over a year now and have been quite pleased with it.
  • johnjani4johnjani4 Member Posts: 1
    I own a 2006 Tacoma 4wd automatic,the 4wd selector is on tha instrument panel.its stuck in 4wd low, any suggestion ?
  • trebor129trebor129 Member Posts: 176
    Here is a paper on how Active Trac works:

    http://classes.engr.arizona.edu/engr498a/2006/fsaediff/resources/techart3.pdf
  • trebor129trebor129 Member Posts: 176
    Ok, now it is obvious to me why electronic stability control cannot work if you lock differentials. So I am now convinced Active-Trac is the best system for driving at highway speeds in snow. It also seems there is almost no situation where locking the center diff would improve anything so perhaps it is one thing to try if you are stuck, but no need to ever go into that mode in anticipation of being stuck.

    My only remaining question is if it would be better for Toyota to use LSDs rather than open diffs front and rear.
  • wwestwwest Member Posts: 10,706
    I believe it is only ABS and TC that cannot be operational, fully functional, with the center diff'l locked. Except for A-LSD (brake implemented LSD functionality) the front and rear diff'ls are still mechanically "open" R/L-L/R differential braking can still be used for stability control.
  • buskybusky Member Posts: 2
    my 07 tachoma top hwy mpg is 15.5 dealer says no check engine light no problems, they suggested putting different tires on the truck,(my wallet), the tailgate was replaced at 1,500 miles because it would not hold the weight of my harley, the plastic compartments in the bed keep falling out, right rear speaker rattles, hood flops from windgusts. FOR SALE only12,000 miles. i bought this truck on the reputation of past toyota trucks, so much for that.
  • canddmeyercanddmeyer Member Posts: 410
    I thought this was the "Toyota 4WD systems" forum, but I'll address your post. First, try posting in the Tacoma forum for more responses related to your Tacoma. Second, it's wintertime, when MPG usually takes a dive due to different gasoline formulations and of course cooler weather. Third, Michelin and Dunlop tires give better MPG than Bridgestone's. Fourth, the speaker and hood adjustments can be taken care of under warranty. Fifth, the tailgate shouldn't be expected to support the weight of an 800lb or heavier Harley. Sixth, no vehicle is perfect. My 4Runner had the radio replaced at 1100 miles and the VSC warranted at 11,000 miles. I've had no problems since except for lousy dealer maintenance..

    You won't have any trouble selling your vehicle should it not meet your expectations. Your post makes it appear though you needed a vehicle with a longer bed to begin with so your Harley wasn't riding on the tailgate. My neighbor has the same vehicle as yours in the DC configuration and has had -0- issues. Another neighbor got a DC 4X4 shortly thereafter, and has no complaints either. Both are 2007 models.
  • tidestertidester Member Posts: 10,059
    You'll want to ask in one of the Toyota Tacoma discussions.

    tidester, host
    SUVs and Smart Shopper
  • cubanpete2cubanpete2 Member Posts: 6
    Cliffy1: As someone trying to buy either a 2005 or 2006 Toyota HLander, your postings are invaluable. Far more understandable information than any dealer I have talked to. I travel a lot of semi-rural back roads in a variety of weather conditions (snow, sleet, rain) and sometimes in Northern Maine I have to drive logging roads for several miles. Am I right in assuming that I should hold out for a 4WD HLander and not touch anything else (e.g. "all wheel drive") or any system that doesn't specifically have the 4WD designation on the rear of the car body? I am completely confused by the designation 4X4 on some cars I have been shown. Any advice to this vehicularly challenged individual would be most appreciated.
  • wwestwwest Member Posts: 10,706
    The Highlander is NOT 4WD as defined by most knowing folks.

    The Highlander is F/AWD, and that for marketing purposes only.

    Note that there is a MYRIAD of F/AWD implementation methods out there in the marketplace, all with varying degrees of multi-wheel drive capability. The Acura/Honda SH-AWD system likely being the best of them, but in my opinion still inadequate for the conditions of travel you encounter.

    The Highlander uses three, front/center/rear, fully open differentials and would therefore be a 1WD vehicle were it not for the electronic braking capability provided by the TC, Traction Control, system.

    Many owners are already complaining that the TC system is totally inadequate for getting the vehicle unstuck, or even up and going on a slippery surface initially as long as TC is active.

    As a result some Toyota and Lexus F/AWD vehicles now have a TC disable function so the driver can use at least some level of wheelspin to get unstuck or rock back and forth to get unstuck. But one must keep in mind that with TC disabled you are back to 1WD.

    Toyota is also introducing a new form of TC called A-LSD, so far only installed on RWD or R/AWD vehicles, and apparently only activated if primary TC is disabled. A-LSD stands for Automatic Limited Slip Differential.

    It has always made sense to have LSD for a rear differential but somewhat hazardous, absent some driver familiarization training, for implementing at the front differential.

    IMMHO the vehicle you're really looking for is the Toyota 4runner. The 4runner has RWD mode, AWD mode, and most importantly for those logging roads, TRUE 4WD/4X4 mode, capability.

    But the key question to ask those salespersons is if the front driveline can be locked, SOLIDLY LOCKED, to the rear driveline for travel on those several miles of logging roads in the wintertime, or MUDDY spring. And I would be sure, CERTAIN sure, that whatever vehicle you purchase also has some form of rear LSD.
  • trebor129trebor129 Member Posts: 176
    The Sequoia 2008 seems to be able to fully lock the front to the rear. I saw the button in the Platinum I was in.

    As for the Highlander, I thought it had a viscous fluid unit between front and rear which automatically stiffens if there is a difference in speed. I would call this a form of limited slip and not 'open.'
  • wwestwwest Member Posts: 10,706
    The early RX300 AWD model did have a VC across the center diff'l but that design was dropped with the introduction of the RX330 series in '04 in favor of only the TC system for AWD capability. I understand it is the same for the HL and Sienna, at least the last I checked with the documentation at techinfo.toyota.com.

    Lexus.com still indicates the RX350 has a VC but the documentation indicates that it does not. I'm in an ongoing argument with Lexus customer service about this at this very moment.
  • trebor129trebor129 Member Posts: 176
    It would seem like the auto-wheel-braking traction control combined with a front, rear, and center limited slip would be the single best system. That is what a 1999 and newer Hummer H1 uses. They use three Torsen diffs though I am not sure exactly which model Torsen.
  • nedzelnedzel Member Posts: 787
    I agree with wwest. The 4Runner has a far more sophisticated and capable AWD/4WD system than the Highlander and will do far better offroad and on bad logging roads than a Highlander.
  • wwestwwest Member Posts: 10,706
    If you have mechanical front/rear/center LSDs why would you even need auto-wheel-braking traction control..??
  • trebor129trebor129 Member Posts: 176
    "If you have mechanical front/rear/center LSDs why would you even need auto-wheel-braking traction control..??"

    Because the LSD is not as good as a locking differential when there is zero traction such as when one tire is in the air.

    But if the car can detect that tire slipping and use the brake just on that wheel, it can force 100% of the torque to other wheels. This comes close to the performance of a fully locked differential.

    A LSD does not redirect all the torque, just some percentage of it.

    My 1997 Hummer H1 had all limited slip differentials and the instruction manual said that if one wheel was in the air, you could force it to not spin by applying the brakes. The Torsen diff would then act as a torque-multiplier and make the other tires overpower the brakes and move. In 1999 they improved this by having a computer just only apply brakes to the wheels actually slipping instead of all of them. They still kept the LSDs. As far as I can tell, it is the ultimate full time system and probably just as good as 3 locking diffs without having to turn them off on pavement.
  • naatz1naatz1 Member Posts: 188
    Interesting how I got to the RAV4 and this forum, clicking on an ad from Edmunds on a quiet Sat afternoon ...I'd watched this forum a bit last Spring as a current 01 Jeep owner thinking I would try a Toyota RAV or new Highlander to get better mpg. After research into Toyota 4wd last summer, yes the mpg was better but those 2 vehicles did not qualify to tow w/margin a 3000 lb boat (needing $800 tow hitch classII option), nor did their 4wd systems make me feel confident living in Minnesota backroads (where we are having an old fashioned 18" of snow in Dec winter so far). I did not fit in a 4 runner w/low ceiling height and despite me liking the retro FJ, one look of the wife convinced me it was too truckish for her, no Jeep Wranglers either.

    So we bought another new Jeep Grand Cherokee with true 4WD ie lo range & 6500 class4 towing. I'd thought about the new 08 Liberty but the JGC handled night/day better. I also liked the Commander but the 3rd seat was a joke. Yes the Jeep only gets 15 city/20 highway mpg ($300/year for gas than a Highlander or Rav6) but it has a lifetime drivetrain warranty and our 01 was very reliable .

    No debate on it's 4WD system either if you need true 4WD QuadratracII does it.
    See the Edmunds Gr Cherokee forum for info http://townhall-talk.edmunds.com/WebX/.eea4ead/1030 or http://www.wkjeeps.com/wk_4x4.htm
  • kurtamaxxxguykurtamaxxxguy Member Posts: 1,798
    Interesting discussion as to how Toyota "AWD" works (I added the quotes because it seems their systems are more reactive than proactive). It does not inspire confidence.

    Does Toyota actually brake spinning wheels to improve traction from the remaining wheels, or do they cut engine power to keep the spinning wheel from spinning?

    But as I am considering a RAV4 "AWD" .vs. Subaru Outback AWD .vs. Subaru Forester "AWD" (that system's more reactive than the Outbacks'), some comments would be welcomed.
  • trebor129trebor129 Member Posts: 176
    "Does Toyota actually brake spinning wheels to improve traction from the remaining wheels, or do they cut engine power to keep the spinning wheel from spinning? "

    The car brakes just the spinning wheel. It can also cut some engine power as needed, but the braking is what forces the torque to move through the diff to another wheel.

    I think my 1999 Mercedes SLK only cut engine power but I am not sure.
  • wwestwwest Member Posts: 10,706
    Since the front wheels are the primary drive I wouldn't be too sure just a single front slipping wheel would be braked. Differential braking at the front might result in such a great level of torque stear that thumbs and fingers might get bruised and maybe even broken.

    So if a front wheel spins/slips then both front brakes are applied and the engine is simultaneous dethrottled to prevent subsequent brake/rotor overheating and warping.
  • 2toyotas2toyotas Member Posts: 104
    Wwest if you look on techinfo.com under new features for 2007 RX350 you will see that the VC was added again for 2007. It was not added to the Highlander for 2008, which I do not understand why.
  • wwestwwest Member Posts: 10,706
    Toyota has renamed VSC/TC/BA/EBD/etc. to VDIM. Supposedly as a result of "tighter, closer system integration but I suspect more of a marketing move.
  • lucky_777lucky_777 Member Posts: 205
    In my understanding Toyota 4WD system on HL, RAV, Siena, etc... never meant for true off road. These vehicles designed for city driving and most never in live drive off the pavement. Toyota 4WD system improves driving in snow or rain, and can get vehicle unstuck from the snow (you might need need to disable VSC in some cases but it will get you out of snow!). These vehicles have improved drive ability in poor weather conditions without sacrificing a lot in fuel efficiency comparing to "real 4WD".
  • cubanpete2cubanpete2 Member Posts: 6
    Just bought a 2005 4wd Highlander from a dealer with Toyota Certified guarantee--covers drive train and major things for another 75k (Car has 23k) or 2015--whichever comes first. For $1700 I can purchase a warranty on a huge number of other things, including electronics etc (not tires and brake pads) I have to buy before I pick up the car (they are putting in some stuff) Anyone have an opinion as to whether I should purchase this "platinum" warranty? Or is it a scam? Opinions desperately welcomed! Thanks in advance.
  • wwestwwest Member Posts: 10,706
    Actually it's TC, Traction Control that might need to be disabled, but keep in mine that when you do that you end up with a "1WD" vehicle if on or in a slippery surface. VSC uses the brakes but only to prevent over or under stearing, plowing or skiding.
  • lucky_777lucky_777 Member Posts: 205
    Right, this is TC. It only needs to be disabled on rare occasions when vehicle gets stuck in the deep snow. Enable it back once vehicle is out of it so you'll be safe on "slippery surface". I know that HL 4WD inferior to Jeep (that designed for off road in mind). I'll take HL 4WD gas savings over superior off road handling of a Jeep or a Hummer. I feel that for everyday commuting HL 4WD is overkill and even 2WD will get you safely anywhere.. I got 4WD more like additional safety feature in the family vehicle and it will serve that purpose.
  • wwestwwest Member Posts: 10,706
    Other than an actual transfer case in order to have a low, granny-grunt, gear range I'm not sure there is enough weight difference between the HL with only a PTO and a 4runner.

    Then there is the BMW X3/5 with REAL AWD, R/AWD.
  • bobwileybobwiley Member Posts: 241
    Check Crown Toyota in Topeka KS or Greenfield Toyota in MA--they offer "greatly discounted" Toyota Extended Warranty's. I'm not at home, so I can't get you ph #'s. In some of the other Toyota Forums they have the info. You can get a 100K 7 Yr Toyota Bumper to Bumper Warranty for about $990. In case you've already purchased it from the HIGH PIRICED dealer--you can still turn it back to Toyota for I think a $50 admin fee. Yes, it is the SAME warranty--the administrative office is in Cedar Rapids, Iowa. I know, I bought from the dealer and learned about the discounted waranty on this Forum. Very EASY process to get a discounted warranty. Look under the Toyota Avalon Forums--I know the reference is there for the dealers willing to discount. Find out the price and then negotiate with your dealer. The Finance guy is the one who gains on the deal!! Good luck!
    Bob
  • trebor129trebor129 Member Posts: 176
    Just pay for your own repairs. They obviously take in more money than they pay out. That is how they profit on it. What that means is that -- paying for a warranty is really a bad deal. Worst of all it adds nothing for the first three years so they just invest the money and try to grow it by the time they might have to pay.
  • lucky_777lucky_777 Member Posts: 205
    I paid $560 for 4WD HL 7y/75k Toyota platinum warranty with $0 deduct from Toyota Midwest superstore in Kansas back in September. Most likely I'll never use it but who knows...
  • derekgaddyderekgaddy Member Posts: 32
    "Just pay for your own repairs. They obviously take in more money than they pay out."
    Is a game of volume...like insurance. That's how they make money. If it makes you feel better having the added protection then by all means purchase the warranty. You probably have better than a 50% chance you'll use some or all of it and recoup your cost anyways.
  • harboharbo Member Posts: 136
    My opinion ...... if you run a 4WD and use it hard buy the extended warranty. If you run a 2WD mostly over the road, no need.
  • zingaro_momzingaro_mom Member Posts: 1
    Hi: Just purchased a new Tacoma and while driving home the 4 Wheel Indicator light (the icon in the dash that looks like a set of 4 wheels with the axle/transaxle) kept flashing on and off. The 2/4 wheel drive selector knob was pointing to 2H...so it should have been in 2 wheel drive. I stopped, put the vehichle in park, set the knob to 4H and then (pushed) and put it in 4L and then back to 2H. Still had the flashing light. It also "felt" like it was in 4 wheel drive...but am not 100% sure it was.

    Any way to know whether it is in 4 Wheel drive, other than depending on that "4 Wheel light" indicator on the dash?

    I plan to take it back to Dealer, but just wanted to get some insight from unbiased folks.

    Thanks, Zingaro_Mom!
  • wwestwwest Member Posts: 10,706
    Sorta just guessing but the flashing icon generally means the drive system is in transition, in the process of shifting from 4WD to 2Wd or vice versa. Sounds as if yours is stuck in between.
  • hdfatboyhdfatboy Member Posts: 324
    "Just pay for your own repairs. They obviously take in more money than they pay out. That is how they profit on it. What that means is that -- paying for a warranty is really a bad deal. Worst of all it adds nothing for the first three years so they just invest the money and try to grow it by the time they might have to pay."

    I think the Toyota warranty is actually a pretty good deal if you have any intention of keeping the vehicle for 100,000miles. I think it is almost a given that something is going to break on the 08 Sequoia between the 3rd year and the 7th year of ownership or between 36,000miles and 100,000miles. Even more likely given its a new model with a new engine, new rear suspension design, new electric seat design, new 6sp transmission design, new 4wd system design, etc.

    I am equally sure that whatever breaks during that period is likely to cost significantly more than $1000. Combined with the fact that unlimited towing and a rental car is included in the Platinum warranty, it seems a pretty reasonable bet to purchase a 7yr/100,000mile/$0 deductible from Toyota, particularly if you can purchase it for under $1000.
  • hdfatboyhdfatboy Member Posts: 324
    It really depends which Toyota 4wd system you are referring to. The new system in the 2008 LC, Sequoia, LX570, 4Runner and LS600h uses a mechanical LSD for the center differential which is not the case in the 4wd systems of Toyota's lower priced vehicles or last year's models.

    This newer system does not exist on most of their older models (I think it was on the older 4Runner models). I believe there is still a significant disadvantage that remains in Toyota's A-LSD system.... it does not function above 35mph. This limitation means that for all of these Toyota vehicles with the new 4wd system, when operating above 35 mph, they really only have traction to one wheel on the front end and one on the rear distributed through the mechanical center differential (the rear differential is still open on the new 4wd system). This can make a difference on wet highway ramps and other higher speed situations (above 35mph) where traction at all 4 corners is desirable.

    The power is distributed through the new Torsen Center Differential with a range of 30/70 upto 50/50 when operating in full-time 4wd. The other downside to Toyota's A-LSD is that because it is based on using the brakes to distribute torque when there's slippage (below 35mph), it can have a tendency to wear out brake pads sooner than a system that doesn't use brakes to distribute torque (ie, mechanical LSD or lockable LSD). I don't know how much additional wear there is but it must be something vs a non-brake method for distributing torque during slippage.

    Toyota's new full-time 4wd design is better (for on-road use) than the old system which had 3 open differentials, but its still not as good as AWD systems used by Audi, Subaru, Dodge, GMC and Cadillac that use a LSD for the center and the rear of their FT 4wd drivetrains.
  • wwestwwest Member Posts: 10,706
    "..when operating above 35MPH...."

    In normal, non-adverse roadbed, conditions none of these engine/transaxle combinations will produce enough torque to induce wheelspin/slip above 35MPH, so above that speed the number of driven wheels is generally not of matter.

    If you have reached 35 MPH and the roadbed is slippery enough that the engine will induce wheelspin/slip and you force it to do so you simply do not belong on the same roads as others with more common sense.

    With A-LSD I suspect the manufacturers have an expectation that over time the drivers will adapt to "learned" road conditions and thereby do their own "feathering" of the throttle to avoid wheelspin/slip. That should avoid most uses of the brakes to implement the A-LSD system.

    The TC, Traction Control, system in my '92 LS400 works very well as a warning, heads up indication, of roadbed conditions for which I may have been unaware, was unaware, but once I get that warning I typically turn it off and drive a bit more cautiously, as conditions warrant.
  • hdfatboyhdfatboy Member Posts: 324
    "In normal, non-adverse roadbed, conditions none of these engine/transaxle combinations will produce enough torque to induce wheelspin/slip above 35MPH, so above that speed the number of driven wheels is generally not of matter.

    If you have reached 35 MPH and the roadbed is slippery enough that the engine will induce wheelspin/slip and you force it to do so you simply do not belong on the same roads as others with more common sense."

    Your view may be reasonable however there have been enough circumstances where I was on a sloping ramp in snowy or wet conditions that I was glad I had a true AWD/FT 4wd system that incorporated a mechanical LSD in both the center and rear differentials. Obviously Toyota engineers felt it offered enough of a benefit to warrant their change over to a mechanical center differential on their newest high-end 4wd models. I just wish they had done the same on the rear differential for the same reason they elected to incorporate it into the center differential.

    I would think MB, Audi, Subaru, GMC, Dodge, Cadillac, BMW, Chevy, Land Rover, Porsche designed their AWD/FT 4WD systems with a mechanical LSD in both the center and rear of their drivetrains for a good reason. IMHO that reason being that it delivers a more sure-footed driving experience without the speed limitations and brake wearing downsides of the Toyota electronic approach.
  • wwestwwest Member Posts: 10,706
    Are you really sure that all those you named, AWD/FT 4WD systems, truly have a rear mechanical LSD..?? When the primary drive is not at the front a rear mechanical LSD vs a brake implemented LSD might make little difference in actuallity, all conditions.
  • hdfatboyhdfatboy Member Posts: 324
    wwest,

    Here's an article that might be of interest on the differences between AWD & 4WD.
    http://www.omninerd.com/blogs/4WD_vs_AWD_and_the_Fallacy_of_Snow_Traction

    2008 Audi S4 Quattro http://consumerguideauto.howstuffworks.com/2008-audi-a4-5.htm
    "4.2-liter 340-horsepower V8 engine, 6-speed manual or 6-speed automatic transmission w/manual-shift capability, all-wheel drive, front and rear limited-slip differentials".

    2008 Chevy Tahoe LTZ 4WD http://autos.yahoo.com/chevrolet_tahoe_ltz_4wd-review_article/?source=nctd
    "a limited-slip rear differential"

    2008 Subaru Baja http://www.allautoreviews.com/auto_reviews/subaru/suburu-baja.htm
    "5-speed manual transmission full time 4WD viscous center differential center locking differential rear limited slip differential"

    2008 GMC Denali http://www.motortrend.com/cars/2008/gmc/yukon/denali_sport_utility/553/specifica- - - tions/
    "Rear limited slip differential "

    2008 Cadillac Escalade Same as Denali

    2008 Dodge Dakota 4WD http://www.dessources.com/en/newcars/perfectcar/index.spy?carid=1081500811&ORIGI- - - N=0&DEALERCODE=514DESSOURCESDODGE&lng=en
    "Limited-slip rear differential"

    2008 Mitsubishi Lancer Ralliart http://www.autoblog.com/2008/01/13/detroit-2008-2009-mitsubishi-lancer-ralliart-- - - were-sold/ "4wd Lancer Ralliart is also equipped with front helical limited slip differential and a rear differential mechanical limited slip differential"

    2008 BMW All M series and Z series vehicles have mechanical LSD in the rear. It is unclear what type of differential is used in the rear of the X series. They do use a mechanical LSD for the center but I was unable to find info on the rear. http://www.motortrend.com/cars/2008/bmw/x5/specifications/

    2008 Land Rover LR3 http://www.automobilemag.com/am/99/2008/land_rover/lr3/hse_sport_utility/877/pac- - - kages_options.html
    "Heavy Duty Package - $625 Rear limited slip differential"

    2008 Porsche Cayenne http://www.allautoreviews.com/auto_reviews/porsche/porshe-cayenne.htm
    "6-speed shiftable automatic transmission descent control four wheel drive full time 4WD hi-lo gear selection front, center and rear locking differential"

    2008 MB 4matic http://www.edmunds.com/mercedesbenz/sclass/2008/review.html
    This is a new system for 2008 and appears to have a mechanical LSD for the center and electronically locking front and rear diffs. The S63 does have a rear LSD. "a performance package for the S63 provides a limited-slip rear differential"
  • wwestwwest Member Posts: 10,706
    "..provides a limited slip rear differential"

    Uisng a viscous clutch, a spring pre-load clutch set, or....

    the brakes...??
  • 2toyotas2toyotas Member Posts: 104
    You should really know more about Toyotas 4WD Systems before commenting. First, the Torsen Center Differential has been in the 4Runner since 2003, and in the Sequoia since 2005. Second ALSD only operates in 2WD, and is engaged by pressing a button. All other times TRAC is on, and works at any speed. TRAC will brake the slipping wheel and cut engine power for stability, which is what you would want above 35 mph. ALSD will brake the slipping wheel to give equal power to each wheel. When these vehicles are in 4WD ATRAC operates at all speeds on both axles. When the center diff is unlocked the Torsen will split power 40 front and 60 rear in normal driving, and up to 53% of power can go to the front, and 71% can go to the rear. ATRAC will brake spinning wheels and cut engine power for stability. When the Center Diff is locked power is split 50/50 and ATRAC will just brake spinning wheels, it does not cut engine power. When LOW range is engaged ATRAC does not cut engine power, and brakes wheels to keep driveability, instead of stability. This is on both front and rear axles, and is said to be equal to a vehicle with the center and rear diffs locked. A Sequoia, 4Runner, or Land Cruiser/LX570 will go farther without getting stuck than any Cadillac,Denali,Audi, or Subaru.
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