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Toyota 4WD systems explained

2487 messages,  Last post on Apr 28, 2012 at 12:48 PM

You are in the Toyota Land Cruiser Forum.

What is this discussion about? Toyota Sequoia, Toyota Highlander, Toyota 4Runner, Toyota Land Cruiser, Toyota RAV4, Toyota Tacoma, Truck, SUV

Messages Page 248 of 250

#2464 of 2487 2011 Sequoia 4wd by 2000lc

Sep 23, 2011 (1:29 pm)

I am looking for a simple explanation describing the applicable conditions (when to use each and why) for using the (1) Auto LSD System; and (2) (when and why) to disable VCS or A-Track. This will sound dumb, but the Owner's Manual I think needs some interpretation to become clearer...Trac Off mode, Auto LSD mode, VSC off mode. Am I supposed to advance from Auto LSD to VSC OFF mode when I am trying to get unstuck, which I seem to be reading is a 2 -step process? Am I close to understanding this?

#2465 of 2487 Re: 2011 Sequoia 4wd [2000lc] by wwest

Sep 24, 2011 (9:47 am)

Replying to: 2000lc (Sep 23, 2011 1:29 pm)
The base problem arises from the fact that selective frictional braking is used to implement Trac, LSD, and VSC. If a condition requiring consistent, continuing, selective braking were to occur and the engine not be automatically dethrottled you would end up with warped brake rotors soon thereafter, or possibly engine failure of the drive train due to the extreme stress involved.
 
Since the driver cannot be trusted to lift the gas pedal to the point of "feathering" when one of these modes activates the system does it automatically for you.
 
So the only method for getting unthrottled wheelspin as a last resort to get unstuck, etc, is to disable ALL of these functions.

#2466 of 2487 4wd won't engage on 2005 sequoia by hankerkid

Nov 14, 2011 (7:43 pm)

Ok, so I guess I forgot to turn my 4wd on once a month on my 2005 toyota sequoia. From what I read online it is in the owners manual. Would have been nice for the dealer to tell me that when I bought it. Now when I hit the button it just blinks on the dash and never locks in or changes. The dealer wants to charge 92.00 just to look at it. I read on this forumn about a fix for my back window (got the defrost and wiper working which is all I wanted, so thanks to all for that). Any idea on my new issue? Hoping there is a way to reset it or get it to engage without a dealer charge. I wasn't able to find anything online other than one guy who took it all apart and replaced a bunch of stuff. I am not mechanical but also not an idiot so I could do minor things.
 
Please help as winter is here in Wisconsin.

#2467 of 2487 Re: 4wd won't engage on 2005 sequoia [hankerkid] by wwest

Nov 16, 2011 (8:08 am)

Replying to: hankerkid (Nov 14, 2011 7:43 pm)
It's sometimes easier for the 4WD clutch to "slip" into engagement accelerating, EASY acceleration, from a full stop, at a low speed, stopped, or even driving slowly, DEAD slow, in reverse.
 
It's even worse if you have new tires at one end vs the other.

#2468 of 2487 Re: 4wd won't engage on 2005 sequoia [hankerkid] by walisprecision

Nov 29, 2011 (7:48 pm)

Replying to: hankerkid (Nov 14, 2011 7:43 pm)
I have a 2003 4runner 4x4 v6 and just went through an ordeal with this but don't dispair. The problem lies in the actuator that is within the transfer case. It along with the front diff actuator are 9vdc and NOT 12vdc. This actuator inside the transfer case drives a pin that makes the transfer case go into 4wd high and then into 4wd low. The actuator is 1200-1300 alone. Aparently this is a weak link on these vehicles. I also am looking at a solution to this issue. For now I have a 4runner with this issue. With a lack of use the pin inside the transfer case becomes gummed up in its housing and gets stuck in one position or another. Mine was stuck in the 4wd low and required removal and rebuilding of the transfer case to free this pin. Sometimes a tap with a rubber mallet can free the pin but this didn't work for me. Good luck.

#2469 of 2487 Re: Highlander and RAV4 [jmay] by reneeg1

Jan 02, 2012 (6:16 pm)

Replying to: jmay (Jan 14, 2006 1:11 pm)
I am having the same problem... I have an 07 Highlander and the back has the 4wd emblem, however, there are no switches that indicate whether or not it is engaged. I recently had to drive through about 6 inches of snow, and I was all over the road, was kinda like riding a Squirrel. I also am not sure what the ect snow button does or does not do. When I had this turned on, the highlander was not any better driving in the snow.

#2470 of 2487 Re: Highlander and RAV4 [reneeg1] by vavavavolvo

Jan 09, 2012 (6:41 pm)

Replying to: reneeg1 (Jan 02, 2012 6:16 pm)
Squirrels are agile creatures. Most of us would prefer a large squirrel in snow.

#2471 of 2487 Re: Highlander and RAV4 [vavavavolvo] by kyfdx HOST

Jan 10, 2012 (5:19 am)

Replying to: vavavavolvo (Jan 09, 2012 6:41 pm)
And yet, squirrelly is a negative attribute, when it comes to vehicle handling characteristics...

#2472 of 2487 Re: Highlander and RAV4 [reneeg1] by wwest

Jan 11, 2012 (10:11 am)

Replying to: reneeg1 (Jan 02, 2012 6:16 pm)
Yes, about all you get with an HL F/awd is that emblem.
 
The HL uses three fully "open", free-wheeling, diff'ls, front, center, and rear. The only time you will hav decent 4WD functionality is when all four tires have roughly equal traction......a whole lot of good that is.
 
One wheel/tire loses traction and limits the engine drive torque to ZIP, ZERO.
 
As of 2010 the RX350 adopted the new Venza F/awd technique, not as functional as would be the Honda/Acura SH-AWD system, but a substandual improvemnt none-the-less.
 
In the class/price of teh HL look to the 4runner, R/awd, for a much more functional AWD/4WD system

#2473 of 2487 Re: Highlander and RAV4 [reneeg1] by luckyseven

Jan 11, 2012 (10:56 am)

Replying to: reneeg1 (Jan 02, 2012 6:16 pm)
Highlander has very effective AWD system that had proven itself to pretty much every HL owner. wwest never owned or rode a HL but has his own, not shared by anyone home grown conspiracy theories about Toyota AWD implementation in HL.
 
HL doesn't have any switches to engage AWD, it on all the time. Use common sense, make sure that your tires are good and suitable for snow/all weather driving. If road really icy and slippery then no AWD in a world will compensate fully for hazardous road conditions. I own 2008 HL and really like 'snow' button functionality under heavy snow. It changes transmission shifting points so car feels more steady when accelerates on the snow.

Messages Page 248 of 250

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