Last post on Aug 21, 2013 at 5:16 PM
You are in the Toyota Land Cruiser
What is this discussion about?
Toyota Sequoia, Toyota Highlander, Toyota 4Runner, Toyota Land Cruiser, Toyota RAV4, Toyota Tacoma, Truck, SUV
#4 of 2493 Tacoma and Tundra
May 16, 2001 (3:00 pm)
These are typical part time systems. Under good road conditions, you are in 2WD with the rear axle getting all the power. Power is again split between the right and left wheels. An open differential will route all power to one wheel if it can turn faster than the other. If this happens, engage the 4WD system. This sends exactly half the power to the front axle where another open differential splits power. Between the front and rear axle, you will normally be able to gain forward traction but because of the open differentials, there is a possibility that you wont. Open differentials are vastly more reliable and longer lasting than limited slip differentials, which is why Toyota has stuck with them.
With this part time system, you can engage it up to 62 MPH (50 MPH if you don’t have a push button system) but it really isn’t appropriate to drive it at this speed. Because the front and rear axles are turning at exactly the same speed, you can damage the system on dry pavement. This system is only appropriate for more severe conditions.
The advantages to this type of 4WD are simplicity and speed of engagement. You are not relying on brake sensors for your 4WD system and it should be more rugged. Also, unlike the Sequoia and 4Runner, the system engages the moment you shift into 4WD. The other models take several seconds and feet to engage.
#5 of 2493 Highlander and RAV4
May 16, 2001 (3:01 pm)
These utilize a limited slip center differential and open front and rear differentials. It is a viscous coupling center differential. If one of the front wheels begins to spin faster than the rear, the heavy liquid in the center begins to firm up which routes more power to the rear. Once torque is equalized, the 50-50 power split is resumed. This system is always engaged and requires no driver input.
It is possible to become stuck with this system. This is because of the open front and rear differentials. If both right tires were on ice, all power would be routed to these wheels. This is a fairly unlikely occurrence on a light duty vehicle like these. On the Highlander, you can get VSC, which includes traction control. If the right wheel begins to slip, brakes are applied to this wheel and power is sent to the left. On the 4WD model, there is no rev limiter associated with the traction control.
#6 of 2493 4LO
May 24, 2001 (1:44 pm)
On the 4Runner can you use 4Lo without locking the center differential? If you can, you still have traction control I assume.
May 26, 2001 (9:47 am)
That is correct. On the Runner, you can run with the full TRACS/VSC system in 4 Low or lock up the center and have a conventional 4WD system.
#8 of 2493 question
Jun 04, 2001 (6:42 am)
on 4Runners. Can you use the 4 wheel drive in hi mode when driving on snowy highways? I know you're not suppose to on Dry roads. How much benefit do you get from the locking diffy when off-roading? Don't see many 4Runners with this option. Looking at possibly getting a used 4Runner.
Jun 05, 2001 (5:25 am)
I thought Toyota got rid of the locking rear diffy on the 2001's? I thought I also read somewhere that this option can't be had with an automatic transmission?
Jun 05, 2001 (11:21 am)
My first question for you is, what model year is your Runner? If you have a 2001, there is a center differential lock, and that places it into a conventional part time 4WD mode. This should not be used on dry pavement. With the 2001, it is safe to use 4WD high (unlocked center differential) on dry pavement.
If you are talking about an older one, they had a conventional part time system. Read back to the section here that discusses the Tundra and Tacoma systems. That should answer your questions.
Jun 05, 2001 (6:11 pm)
To summarize, do you mean to say the the HL with 4wd and VSC is the least likely to get stuck in moderate snow conditions? Also, is the limited slip dif a clutch or plate type? What is the likelyhood of its needing service?
Thanks for all your informative posts.
#13 of 2493 looking at used '99 SR5 v6 4x4
Jun 06, 2001 (3:55 am)
if I can only use the 4x4 off road, then it really isn't worth getting if it can't be used on pavement in snowy or bad road conditions during winter.