Limited, Full-Time 4WD vs AWD Differences

Oh. But in H4F if one front and one back wheel is not getting traction and spinning does the other non spinning wheel on same axel get power tranfefed to it or does all the power go to the spinning wheel?

You are correct. In the unlikely event that one front wheel and one back wheel are completely without traction, you will probably be stuck in H4H, or even H4L. This would most likely only happen in an extreme off-road or extreme ice condition.

In that case, you would put it in L4L and use ATRAC.

In my opinion, the all wheel drive system on the 4Runner Limited is probably the best out there if your primary concern is safely navigating snowy/icy roads.
 
Oh. But in H4F if one front and one back wheel is not getting traction and spinning does the other non spinning wheel on same axel get power tranfefed to it or does all the power go to the spinning wheel?

If ATRAC is engaged, then the spinning wheel will have the brake applied to it, so the non-spinning wheel with grip will get power. But I believe ATRAC only works in low range.

Best would be "lockers". locking differentials, then both wheels are forced to turn at the same speed, and the car will move forward because one wheel has grip.
 
Came here for info on the full time 4wd and this thread delivered. I’ve got my 3rd gen Limited with the “multi mode” t-case as it was called (ie 2wd, full time 4wd, part time 4wd, and 4low). Looking to replace my wife’s Acura MDX with SH-AWD (super handling all wheel drive) with a 5th gen 4Runner with full time 4wd capability. Didn't realize that ONLY Limited 5th gens got that. Wonder why Toyota didn’t even offer it in their TRD Pro models?
 
Came here for info on the full time 4wd and this thread delivered. I’ve got my 3rd gen Limited with the “multi mode” t-case as it was called (ie 2wd, full time 4wd, part time 4wd, and 4low). Looking to replace my wife’s Acura MDX with SH-AWD (super handling all wheel drive) with a 5th gen 4Runner with full time 4wd capability. Didn't realize that ONLY Limited 5th gens got that. Wonder why Toyota didn’t even offer it in their TRD Pro models?
They may have just felt that that demographic wouldn't particularly demand it, being ok with the old school part-time only setup. It certainly costs Toyota more to put in the full-time transfer case, so I could see them avoiding spamming it everywhere.

As far as my '23 ORP, if the full-time Limited transfer case would've been, say, a $1,000 option, I would've possibly gone for it. Although I don't drive on "half icy/snow, half dry" alternating roads all that often, the one use case where I get really envious of it.

I also came from a '99 Limited 4runner with that many-mode transfer case. Having all that AND the factory rear locker was so much versatility!
 
So do the 4wd Limiteds not have the ability to shift into 2wd? Just H4 (similar to AWD), H4L (true 4x4), and L4L (4Low)?

No H2 (2wd)?
 
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Bummer. Seems like the 5th gens got screwed on the transfer cases. I wonder if the VF4AM multi mode t-case from the 4th gen could be swapped in without much difficulty?
Is that really "getting screwed"? For all the effort Toyota went through on the part-time 4WD models to have an Automatic Differential Disconnect when 4WD isn't in use.... the full-time 4WD Limiteds get the same EPA fuel economy numbers, so RWD vs AWD/4WD on the 5gh gen doesn't seem to carry much of a fuel economy penalty....

If I had a Limited, I definitely wouldn't be bummed that I can't put it in 2WD. The only reason I'd want to is if I had to put a non-matching-diameter spare tire on in an emergency; if I had 2WD, I'd put it on the front axle and stay out of 4WD, and if I had full-time 4WD, I just wouldn't do it.
 
Is that really "getting screwed"? For all the effort Toyota went through on the part-time 4WD models to have an Automatic Differential Disconnect when 4WD isn't in use.... the full-time 4WD Limiteds get the same EPA fuel economy numbers, so RWD vs AWD/4WD on the 5gh gen doesn't seem to carry much of a fuel economy penalty....

If I had a Limited, I definitely wouldn't be bummed that I can't put it in 2WD. The only reason I'd want to is if I had to put a non-matching-diameter spare tire on in an emergency; if I had 2WD, I'd put it on the front axle and stay out of 4WD, and if I had full-time 4WD, I just wouldn't do it.

Yes, I really would say that is getting screwed. Going from the super capable multi mode t-case that the 3rd gens (VF3AM) and 4th gens (VF4AM) had, to what the 5th gens seem to have is a downgrade for sure. 4th gens seemed to have the best of it; 2wd (because not everyone wants to be in 4wd all the time, ever blasted around in 2wd w/ rear diff lock engaged?), 4wd w/ center diff unlocked for snowy icy conditions, 4wd w/ center diff locked aka true 4x4 (duh), and 4Lo with center diff either locked or unlocked. I know a lot of people won't care about 4Lo w/ center diff unlocked, except that it's pretty damn useful for when you're trying to reverse with a trailer pushing it up a steep driveway. I modified my 3rd gen to give me 2Lo and it's truly a game changer trying to negotiate the 90 degree turn reversing into my driveway and snaking my boat around the side of my house. Just makes it so much easier. Toyota should've at least given the ORP or whatever their supposedly highest capability trim level is the most capable t-case they could, but instead apparently elected to give it a downgrade from what 3rd and 4th gens had. So yeah, definitely got screwed for sure.
 
This is an old thread, but if you happen to end up here
This is a great video on YouTube that is an old Toyota promotional video about how the different four-wheel-drive systems work.
It shows very clearly how the full-time four-wheel-drive on the 4runner limited works… and how it’s different than part-time four-wheel-drive and all-wheel-drive.
The limited 4Runner more or less has the same full-time four-wheel-drive system that the land cruisers have.

https://www.youtube.com/watch?si=hf4RYK94lj7k60fw&v=pN6-gCxI60g&feature=youtu.be
 
Full-Time 4WD is just like it says on the box. It’s what we have in the Limited. It’s the full-time version of what I’ve just described for our part time friends (specifically open differentials), but with a major distinction: The system employs a 40:60 torque split in most driving situations and alters that in response to slippage. In addition, if the front wheels are slipping while the vehicle is turning, the  center  differential changes the torque split to 30:70. If the rear wheels slip while the vehicle is turning, the split changes to 53:47. This info is taken directly from Toyota: Toyota 4Runner Celebrates Historic Run with 40th Anniversary Special Edition - Toyota USA Newsroom
*note the section, “4x2 and Two kinds of 4x4.”

I looked all over to find the torque split on the Limited 4wd, without success. Thanks for including that!
 
A little more: based on my understanding of an "open" diff, both wheels get power as long as both wheels have traction. As soon as one wheel loses traction, it gets all the power and you... lose forward thrust while one wheel spins. Back in my '60s muscle car days, we'd make fun of the guys who did the one wheel burnouts.

With a limited slip, there is either a clutch setup or a rear torsen (yes, they are used as limited slip diffs too). With the clutch setup it keeps the wheels at roughly the same speed (with some slip) when one wheel slips. Sometimes we'd test for Posi-traction (limited slip) by putting one wheel on pavement and one on the grass and then punching it. Open diff: you'd go nowhere. Posi: both wheels would spin. With a torsen I believe it actually transfers torque to the wheel with more grip (again, example is a rear diff). With either a clutch/disc based or torsen based mechanical limited slip, you'd get two stripes if you did a burnout :) With too much abuse the discs wear and you eventually have what amounts to an open diff.

With braked "fake" limited slip, it's an open diff, but when that one wheel starts whizzing away (loses grip), it gets braked (single wheel braking due to the wonders of ABS tech) and then power is "forced" across the axle. In this case you'd probably melt your brakes if you tried to do a burnout.... But, it would very effectively get you off of that grassy shoulder.


Another way to determine if a rear axle was positraction on a muscle car was to put it on a lift and hand-rotate one of the wheels. If the opposite wheel moved with the same rotation you had a positraction, if the opposite wheel rotated the opposite way you did not have positraction. I had a 1970 Dodge Charger R/T with the Dana 60 rear axle (positraction) and it was a beast.
 
Another way to determine if a rear axle was positraction on a muscle car was to put it on a lift and hand-rotate one of the wheels. If the opposite wheel moved with the same rotation you had a positraction, if the opposite wheel rotated the opposite way you did not have positraction. I had a 1970 Dodge Charger R/T with the Dana 60 rear axle (positraction) and it was a beast.

The Car Care Nut just posted a good basics on Toyota 4WD/AWD (including A-trac, Crawl Control, Multi-terrain)

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Is the 6th Gen LTD still using the same Torsen Diff? I read this recently, although I don't quite understand what he means:

"If you’re considering a 6th gen, I believe (iirc) Toyota added some cost cutting (or profit boosting) options on the full-time 4wd limited trim. Namely, I think they have two full-time transfer case options. One has a locker inside the differential of the transfer case. The other does not, meaning the center differential is always open, which basically makes it perform like a AWD drive car. If you’re planning on driving it off-road, make sure the transfer case has a locking center differential. That way it will drive like a true 4wd vehicle, and it will behave just like a part-time 4wd 4runner off-road."
 
Is the 6th Gen LTD still using the same Torsen Diff? I read this recently, although I don't quite understand what he means:

"If you’re considering a 6th gen, I believe (iirc) Toyota added some cost cutting (or profit boosting) options on the full-time 4wd limited trim. Namely, I think they have two full-time transfer case options. One has a locker inside the differential of the transfer case. The other does not, meaning the center differential is always open, which basically makes it perform like a AWD drive car. If you’re planning on driving it off-road, make sure the transfer case has a locking center differential. That way it will drive like a true 4wd vehicle, and it will behave just like a part-time 4wd 4runner off-road."

6th gen full time 4wd trims use torsen and do not have lockers. there are 10+ trims which ridiculous but the part time 4wd ones only have locking rear diff for certain trims. if you get a limited fulltime 4wd you can lock centre diff and go in true 4x4 mode. Im not aware of any 6th gen trim that has a fulltime 4wd and locking rear diff
 

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