JHupp

Ok, I was never able to find a good answer to all of this. I have read on reviews of the 4runner, and changes from model year to model year that starting with the 99 Limited models, and in

"2001 Toyota 4Runner: 4Runner lost its base 4-cylinder models and manual transmission for 2001, but all models now had full-time 4-wheel-drive and an antiskid/traction-control system."

But I have also read

"The Land Cruiser is always in the 4WD mode. The 4Runner and Sequoia can be used in either 4WD or 2WD. It is safe to leave either in the 4WD mode at all times. You will loose a bit of fuel economy, but will handle better. Unexpected loose gravel and slippery surfaces will not be a problem. "

Which I do not cmpletely understand. The shift lever for my 4wd is always in 4HI, it has no 2wd option on it, as my Fords have had, or Jeeps, or older Toyota do. However, why then would I have to push the 4wd button on the side of my shifter to engage a part time 4wd mode.

Wouldnt AWD imply part time 4wd??
And isnt a full time 4wd just part time or AWD??

From there I understand that locking the center differential gives me a true 50/50 power split, and this is considered true 4wd. A lot of these terms seem to be used quite loosely. I do not plan on doing any serious modding to this truck yet. But one day, some time in the far future, I may SAS it, and I have looked into a crawler.

From what I understand, my truck, a 2001 SR5 does not have a transfer case, instead it is a center differential, but if it is normally in 2wd, wouldnt it need a transfer case?

I honestly do not think that this truck is AWD, I have really been able to kick the ass end out with the TRAC off, and I have never been able to spin either of the front wheels until at least the part time 4wd was engaged via the button.

My basic question is, if the 4runner is a full time 4wd, how is it that I am able to drive in 2wd normally( I think I am)? This would imply that there is a transfer case right? Which I have never heard of, or been able to locate on a 2001?

I am extremely sorry if this has been posted before, I have searched, but it seems in a lot of other threads, there is a great misunderstanding about the systems on the 99 Limiteds and the 2001/2002 4WD 4runners. Just thought that a thread to clear up all of the issues, might be worth it. I know a fair amount about 4wd and AWD, but this setup has me stumped, and the generic edmunds, and car reviews, do not help at all. Thanks!

ecchamberlin

Now you have me scratching my had also. I think we have transfer cases with a center differential. I have spent lots of time under mine and pre 2000 Runners and Tacos and it looks the same as those with the exception of the small motor on the back of the T-case which is the locker. I am almost positive that we do not have AWD because they even say 4WD on them. No power goes to the front of my Rig when the 4WD is not engaged.

I will follow this to see if anyone feels otherwise about this.

JHupp

Yeah, that is basically what I figured too, a transfer case with a center differential, but I have never been able to spot a transfer case. Everwhere I go, they say this 4runner has a full time 4wd system, and it just makes me curious as to why this is sdaid, if it is normally 2wd, and only part time when engaged. It makes 0 sense to me, might just be another mislabeling from the usual suspects.
Here is one site of the many that says 2001 has full time 4wd
http://auto.consumerguide.com/Auto/U...all?print=yes/
And like I said on all of the 4wd trucks I have owned and driven there is an actual 2wd mode on the shifter. then 4 hi, and 4 lo.

ecchamberlin

This is my theory on this.
I think because the 4wd shifter went from a 4 position model (4Lo, N, 4Hi, 2Hi) on the earlier Tacos and Runners to the 01/02 3 position model (4Lo, N, 4Hi) they think it is full time.
What they are not considering is that the front diff is engaged by the button (electronically instead of mechanically) on the side of the the 4x4 shift lever which would bring it back to the 4 position selectivity that was there before.

All 03 and 04 Tacos have the same button on the shift lever that we do and with the exception of the center diff locker are dirivetrain exact matches. No one is saying that the 03 04 Tacos are full time 4x4.

JHupp

Hmm, makes sense, so it would be like an electronically controlled center diff/ or transfer case?

ecchamberlin

Yes I think it is a lot like other push button/dial type of 4x4 systems like on Fords and Chevy's. The T-case is always ready for 4x4 to be engaged through the button and then can mechanically be shifted to or from either 4Hi or 4Lo.

JHupp

ahhh, makes sense to me, sounds stupid to call it full time 4wd if the truck is in 2wd, also, I am assuming that there is a transfer case, howver, if it was electronically controlled, adding a crawler would be impossible, as stated in other threads. I am guessing an eventual SAS may not be out of the question though(although not for at least 3 years).

ecchamberlin

SAS on our rigs has not been done yet becasue the computer is so linked to the ABS systems along with ATRAC and VSC. Most are of the opinion that it is not possible without swapping the computer also from a 2000 or earlier.
Crawlers are also out because the c-diff locker is on the backof the t-case which would be where the crwler would go. No big deal to me I did stuff a Marlin crawlered/locked 1st gen could not do last weekend. (Very cool rig though) Atrac is a very capable system and mine is going no where.
I am however doing a manual hub conversion. ASAP! Broke a CV last weekend ( and fixed it same day) and manual hubs would have been so nice instead of driving 65 miles with a cv banging around. Expensive but worth it IMO. Will also allow up to 3" of front lift as the cv shafts will not be spinning when not off roading.

ecchamberlin

https://www.yotatech.com/forums/show...hub+conversion

Check out the 4x4 shifter on this rig. Can you ee the same 4wd button that we have?

KZN185W

iTrader: (1)

A FULLTIME 4WD vehicle does not have 2WD mode. It is always in 4WD but it has a transfer case (for 4Hi and 4Lo only) which has a lockable center diff inside it that allows differentiation between the front and the rear axles when used on hard surfaces.

Hence, the 3rd gen 4Runner is not a fulltime 4WD vehicle. However, some models are equipped with a transfer case that has a center diff inside. Toyota calls this as Multi-Mode 4WD. By pushing on the 4WD button, 4H is engaged but the center diff is unlocked. This mode allows the 4Runner to run on hard surfaces in 4WD without binding the driveline. In some vehicles, 4H is known as AWD.

Just my .02.

MTL_4runner

This is a great article which clearly explains the difference between 4WD and AWD (and hybrid variations):
http://www.4x4abc.com/4WD101/awd.html

Basically the 4runners will either have part time 4WD or full time 4WD depending on the year.

ecchamberlin

That is a very good article

What I get from it is that the 01/02 is a hybrid between Full time and Part time systems. It does not fit either system exactly.

lee

button not pushed in = 2wd (rwd)
push in the button = awd (rear bias)
lock the ctr diff = 4wd (no rear bias)

when you shift to 4L, it auto locks the ctr diff...

thats about all there is to it.

JHupp

pretty much got that down, but when you push the 4wd button on the side of the stick, is it electronically engaging a transfer case? That is the only scenerario that would make sense. The truck would have to have both a transfer case and a center diff. I was never able to find something that looked like a transfer case under my truck, but I may not be looking for the right object or in the right place. Besides that, this is even more confusing because evry definition of full time 4wd reads something like

"Conventional full time 4WD vehicles use a differential inside the transfer case to make 4WD use on pavement possible. This is done with a ring and pinion set or a planetary gear set. Each of the 4 wheels constantly gets 25% of the torque"

which I don't think is true for the 2001/2002 4runners, but why would Toyota call it this, if it is no where near the truth?

KZN185W

iTrader: (1)

The 2001/2002 4Runners still have 2WD, hence, it's not a full-time 4WD vehicle. Toyota calls it as Multi-Mode 4WD. You have the option of using H4 all the time but you also have the option of using 2WD.

In my opinion, the Multi-Mode 4WD is still part-time 4WD. It's just that it has a lockable center diff.

lee

i agree, its still parttime but i guess you do have the full time option.

4RUNN!N

They also classify the Quadra-Drive 4WD system as a Full-Time 4WD used in the Cherokee/Liberty and Grand Cherokee. Their transfer case shift pattern is

2HI
4HI-Full Time
4HI-Part Time
N
4LO-Part Time

JHupp

hmm, good to know, I'm still wondering if the truck has a transfer case, and how it operates, I am guessing that when you push the button on the stick, it electronically activates the transfer case then? That would seem like the logical setup.

02SE

Maybe this will help you understand. It's my reply to you from the "Does the front driveshaft turn in 2WD" thread.



What that quote from the other site should say, is that 4X4 '01-'02 4Runners have full-time 4WD capability, with vehicle stability control, and traction control.

Just driving along, you are in 2WD, when you push the button on the transfer case shifter, this shifts the truck into full-time 4WD, which can be used anywhere, anytime.

If you then also push the center difflock button on the dash, this connects the front and rear driveshfts together with no differentiation. This is what's known as part-time 4WD. You only want to use this mode on slippery surfaces, otherwise you can get binding in the driveline, which can break parts.

ecchamberlin

Nicely done. No more question. We had the right idea though.