Ask the Car People.SM


Toyota 4WD systems explained

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

You are in the Toyota RAV4 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 249

#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.

#2474 of 2487 Re: Highlander and RAV4 [luckyseven] by wwest

Jan 11, 2012 (6:53 pm)

Replying to: luckyseven (Jan 11, 2012 10:56 am)
Yes, I do not own an HL, but I do own the exacting(***1) equivalent, a 2001 F/awd RX300. Previously owned a 2000 F/awd RX300 which in retrospect I wish that I still had(***2). Due to pretty severe transaxle stress problems, premature failures, with the '99 and then less so the 2000 this early, more functional, F/awd system was abandoned. Those early failures proved to be the result of the rear drive being "automatically" engaged via the use of a VC, Viscous clutch/coupling design used to "lock" the center diff'l.
 
By the time the HL went into production the F/awd functionality had yet again been lobotomized, the VC was eliminated entirely.
 
"..home grown conspiracy theories..."
 
For years now, 10 or so, I have paid the substantial annual subscription fee (techinfo.toyota.com) for full and complete access to ALL Toyota, Scion, and Lexus models. The information I publish here is derived directly as a result of my access to the appropriate factory service/shop manual set.
 
If you suspect otherwise the daily access fee is quite affordable.
 
"..it on all the time..."
 
Pure BS. Anyone with even the most basic knowledge of AWD systems will understand that this just simply cannot be the case. Driveline components would be overstressed, so overstressed, that component failure would result within ~50 miles. Even "partially" automatically engaged, or even "part-time" automatic engagement is proving, right at this very moment, to be a problem with all reasonably functional F/awd system...the best of the best, the SH-AWD system, for instance.
 
"..it on all the time..."
 
No, it's ENABLED 100% of the time. The HL's F/awd system only activates AFTER-THE-FACT, only after FRONT wheelspin/slip is detected via simultaneous monitoring all four ABS "tone" wheels. And while one might think that the process of Trac activation would involve quick drive coupling to the otherwise "free-wheeling" rear tires. But due to serious safety concerns unique to FWD vehicles that is not the case.
 
The first action taken via Trac activation will be braking of the front wheels in order to most quickly restore front traction and thereby alleviate the otherwise strong possibility of loss of directional control. To facilitate even quicker front traction recovery and to prevent overheating of those front brakes should the driver not quickly release the gas pedal the system will also automatically and simultaneously FULLY dethrottle the engine.
 
Many later models, including the HL, using a F/awd technique of this type now have a Trac/VSC disable system so the driver might often have additional resources to get unstuck or initially moving forward on a slippery (uphill) surface.
 
***1 My '01 F/awd has an absolutely USELESS VC mounted across the center diff'l, purpose being to automatically "lock" the center diff'l under conditions of consistent wheelspin/slip. So useless that it was dropped entirely from the RX and HL with the advent of the RX330.
 
***2 My '00 F/awd RX300 not only had a fully functional VC, Viscous Clutch/coupling, it also had the then optional rear mechanical diff'l. I traded up to the '01 to get HID and VSC not realizing that I was giving a more functional, MUCH more functional, F/awd system.

#2475 of 2487 Re: Highlander and RAV4 [wwest] by luckyseven

Jan 11, 2012 (7:11 pm)

Replying to: wwest (Jan 11, 2012 6:53 pm)
You have wonderful theories but they proven to be baseless. Read actual HL owner experiences here
 
linky
 
We've been around this number of times. Just stop posting your useless technical mambo-jumbo and drive a HL in a snow for a change.

#2476 of 2487 4WD or RWD Opinions by txpackersfan

Jan 15, 2012 (6:21 am)

Looking for some opinions here. I'll be buying a Toyota soon (Land Cruiser, Tundra, or Sequoia) and have been debating between RWD and 4WD. I pretty much decided I have no need for 4WD here in TX. When I lived in the upper midwest, it always made sense to have the 4WD for the inevitable winter storms. In fact it was hard to find trucks and SUVs that were only RWD. Now that I'm living in TX I don't really see the need for 4WD yet I often see these trucks and SUVs optioned out with 4WD. Why? What am I missing? You add $3 -$4 grand to the price, add more items that could wear out or fail, and reduce the gas mileage. I've only been in TX a few years so maybe I'm missing something. Can someone tell me why I might need 4WD when living in the South?
 
The only reason I can come up with is I may need it if I take winter trips to visit family in the UP or if I ever move back.

#2477 of 2487 Re: 4WD or RWD Opinions [txpackersfan] by toyodave

Jan 15, 2012 (6:34 am)

Replying to: txpackersfan (Jan 15, 2012 6:21 am)
You might need 4WD to tow a future boat or travel trailer. If you ever decide to sell your vehicle, 4WD is like selling a house with a swimming pool. If the house is good, someone who must have a pool will buy your house over the one without. 4WD is great for off road, but if you have no desire.....not much point there. If you buy the vehicle without 4WD, you can never install it later, should your needs change. 4WD rarely goes wrong in Toyota's but, it does adversely affect the fuel mileage, by maybe 2 gpm's.

Messages Page 248 of 249

To POST a message, please Sign In.

Advertisement

Browse by Category

Browse by Vehicle
   View All Vehicles

Browse by Board
Browse by Topic
View All Topics

Edmunds Community

Advertisement