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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 2 of 249

#11 of 2487 leomort by cliffy1

Jun 05, 2001 (12:21 pm)

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.

#12 of 2487 cliffy1 by squeakersadie

Jun 05, 2001 (7:11 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.
JM

#13 of 2487 looking at used '99 SR5 v6 4x4 by leomort

Jun 06, 2001 (4:55 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.
 
                      Leo

#14 of 2487 looking back at Tacoma&Tundra post by leomort

Jun 06, 2001 (5:00 am)

it appears that I can use the 4x4 during adverse weather condtions on pavement, as long as it's not dry. Just how "bad" is the key.
 
             Leo

#15 of 2487 squeakersadie by cliffy1

Jun 06, 2001 (6:22 am)

On the HL, the least likely version is the 4WD with the VSC. The limited slip differential in the CENTER is a viscous coupling, while the optional rear LSD is a clutch type. The down side to clutch types is that they wear out. When they do, you may not even know it. They will just behave like a normal open type.

#16 of 2487 Highlander , mobile-1 syn gear oil? by teeceeb

Jun 08, 2001 (6:02 am)

Cliffy,
 
  On the awd highlander there is a sticker on the center differential that states 85w-90w , would it be ok to use mobile 1 syn 75w-90w gear oil? you mention that when the front wheels spin faster than the rear, the heavy liquid firms up. so should a 75-140 be better?
 
thanks
tc

#17 of 2487 teeceeb by cliffy1

Jun 08, 2001 (11:08 am)

I'm the wrong guy to answer that question. I am a sales guy and while I have a good level of knowledge of how things work, I leave the actual mechanics to the mechanics.

#18 of 2487 New Landcruiser Owner (relatively new) by roothead

Jun 09, 2001 (6:26 am)

Hi - I just found this board and have a question regarding how to use the different aspects of my 2000 TL's full-time 4WD system. Here is the situation that I got into and I wonder what I should have done differently. Any advice you could provide would be greatly appreciated
 
A friend took his 2000 Montero out into a field to to take his son to a well-stocked pond to do some fishing. Here in Central Ohio, we have gotten 8-9 inches of rain in the last few weeks. All went well for him until he got stock in a low area that quickly turned into a mud hole. He called me and I came over with my tow chain. As I went off the pavement, I continued to stay in 4WD-H mode and easily travel 1 mile back into the field over rolling hills and muddy trails. I place the TL into 4WD-L (after stopping the Cruiser and placing the sifter into "N", I moved the 4WD sifter into the "L" position.) and pulled his Montero out. I then followed him back towards the road. Here is where the problem arose - we needed to go down through a gully that was mud on both sides (down into the gully as well as back up on to "normal ground)and the low point of the gully was 10-12 inches of thick mud. Believe it or not, the Montero went down and up and over to the "dry" side with no problems. The TL and I (still in 4WD-L mode)followed him at a safe distance. All went well until I started to spin the right front wheel. I sat there 1/2 way up the side and started to slide into some trees. I stopped and backed down into the gully until I reached the flat muddy area at the bottom and then tried again - still no luck. Finally, I backed down and turned off the VSC via the dash button, placed the transmission into "N", shifted the 4WD into "H" and hit the gas - up and over I went. My questions are:
(1) What should I have differently so as to avoid the mess that I got into;
(2) under what conditions do I use the 4WD-L mode and when should I ever have to turn off the VSC system?
 
The TLC owners mannual is useless from this perspective.
 
Thanks for your time and assistance.

#19 of 2487 roothead by cliffy1

Jun 09, 2001 (6:36 am)

Interesting set of circumstances. The fact that you were able to get out of the mud hole without a tow speaks volumes about the LC capabilities. To avoid getting stuck in the future, I would suggest keeping it in the high gear range except when pulling somebody else out or when maximum torque is needed. Momentum is everything when dealing with mud.
 
As to when to turn off the VSC (by locking the center differential), this is only a good idea when you need to be able to slip laterally. Driving in sand is a good example of when this works best. I would suspect that you would have been able to get out of the mud with the differential unlocked and the VSC functional. I wasn't there, but it sounds like you handled it well.

#20 of 2487 by drew_

Jun 09, 2001 (10:13 pm)

Don't forget that 4WD Low multiples the torque to the wheels by over 2 times. This means that the tractive limit of the tires is reached faster and hence you can literally dig yourself into a hole by spinning the wheels with so much more torque. This is one reason why 4WD Low shouldn't be used in sand or snow (unless it's really thick and deep snow).
 

Drew
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