Why is V8 Full Time AWD?

It was actually raining today and i pulled up to a stoplight and threw it into 4WD and hammered down and i finally got the front wheels to spin after 80000 miles of trying haha. The 4WD works so dam well in the 4runner
 
There is one scenario where an auto Subaru (at least the base models) are no better than a FWD car. If you are going around a snowy corner a bit fast (like an entrance ramp from one highway to the other) it acts just like a FWD car...useless. I am not sure if my 4R would have acted that way but I gently let off the gas and it went into the widest opposing fishtails I have ever been in. The day after, I had dedicated winter tires. My other tires were like-new Michelin Pilot Exaltos with 2K on them when the incident happened. I was doing right around 55 on a 55 ramp...too fast for that night...it had started to snow. No, i have not attempted to recreate that. :jaw drop:
 
From what I understand...with the center diff unlocked its naturally split 50%-50% but in the event of a slip, you can have a max torque split of 60% Front - 40% Rear or up to 30% Front - 70% Rear. With the center diff locked its 50%- 50% all the time.

Exactly! That is why my 2005 RAV4 was considered full time 4WD even though it did not have low range gearing or a locker, it was the 50/50 split unless the traction control felt otherwise.
 
When I bought mine this summer, I specifically looked for the V8 after I did my research and discovered the gas mileage was for all intents and practical purposes equal to the V6.

The i-Force V8 is a monster of an engine, and all that torque... just so sweet to have if you're doing anything other than flat, boring driving.

I came from a Pathfinder and have driven friends' 4Runners - 2WD SUVs are just awful to drive in the rain/inclement weather, so the full-time 4WD is just awesome. It sticks to the road no matter what.

I wish I could find an official citation, but its actually 60/40 rear/front split during regular driving, and w/o the differential being locked will shift as much as 75 to the rear and as much 53 to the front. I thought 53 was such an oddball number, which is why I seem to remember that.

Fwiw to the OP, I have also been tracking my gas mileage via a log on my phone, testing premium (91 octane) and mid-grade (89), since the V8 calls for premium fuel. I am averaging 14-16mpg. I have found NO DIFFERENCE in the two grades. I plan on switching to regular soon to see if that makes any difference.

I have seen some people reporting 20mpg for the V8, but I think they must be on crack or doing some pretty nifty calculations. For some context, I tow a trailer 3-4x/week, and also work on top of a mountain, which means 5x/week I climb 1200ft in only a few short miles.

All in all though, I'm so glad I bought the V8. The power, the proven track record of that i-Force engine, 5 speed transmission, and full time 4WD... how can you go wrong?!

Oh ya, and would I want a 2WD option? No. Never. We have a Volvo XC70 2.5T AWD and now the full-time 4WD 4Runner - I will NEVER own a 2wd vehicle again unless I have to. Once you've had the regular confidence of AWD at your control, I dont see how anyone wouldnt want it.
 
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I have seen some people reporting 20mpg for the V8, but I think they must be on crack or doing some pretty nifty calculations. For some context, I tow a trailer 3-4x/week, and also work on top of a mountain, which means 5x/week I climb 1200ft in only a few short miles.

Keep it under 60 on the interstate and you'll see 20 mpg easily. Tahoe to San Francisco could get me 22-24 mpg. San Francisco to Tahoe would get me 20-22 mpg. The key was not dropping the hammer.

Now, dropping the hammer on US 50 and blasting away on the road past Placerville to Echo Summit would net me 15-16 mpg.

Done the drive between the two 100+ times.

All the time 4WD is great, not perfect (it takes a few moments to engage) but is a lot better than pulling over or stopping and trying to engage the 4WD.
 
There is one scenario where an auto Subaru (at least the base models) are no better than a FWD car. If you are going around a snowy corner a bit fast (like an entrance ramp from one highway to the other) it acts just like a FWD car...useless. I am not sure if my 4R would have acted that way but I gently let off the gas and it went into the widest opposing fishtails I have ever been in. The day after, I had dedicated winter tires. My other tires were like-new Michelin Pilot Exaltos with 2K on them when the incident happened. I was doing right around 55 on a 55 ramp...too fast for that night...it had started to snow. No, i have not attempted to recreate that. :jaw drop:

Sounds to me you experienced lift off oversteer, you should have not let off the accelerator.
 
The full time 4wd is a bonus, not a detractor. So is the Lexus sourced V8. The whole reason I picked the 4runner over the competition. Like others said, if MPG is more important than body on frame construction, having low range, a 7,300 lbs tow rating, etc- get something that'll do better than 14/17 city highway.

If you're seriously not going to tow or off-road, get a car based SUV like the highlander. More room inside, and much better mpgs. Just no low range or off-roadability and don't try to tow anything with it.
 
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As previously mentioned, if you are concerned about MPG, start looking at something other than a Runner. 75% of my driving is city stop and go. I see a realistic MPG of 13.7 with my V8.

That being said, I wouldn't trade if for the world. This is without a doubt the most reliable and fun truck I have ever driven.
 
I agree with all the posts voting in favor of the AWD V8 as designed...

One thing that hasn't been mentioned is that with an AWD we accept the fact we have more moving parts....resulting in eventual maintenance. I personally provided the opportunity would not disengage the front axles very often.

Back when 4WD's commonly had locking hubs, it used to drive me crazy in foul weather when my buddies, rasied in snow country would continue to drive with the hubs unlocked and the Tfer case in 2WD!!

Anyhoo...if the OP didn't get the message that his supposition was ill founded...then he is not listening or didn't want info.

:roadkill:
 
This forum seems so strange to me in the v6/v8 debate. Every single other automotive circle I've ever been in this is a no brainer, if a v8 is offered you buy the v8. You won't see this on any other forum.

Why buy something you don't need? Why buy something which has an added expense of a timing belt every 100k miles?? Why buy something that has less room to work on the engine? Why buy a vehicle that only has awd? Why buy a vehicle that gets worse gas mileage?

You're right...it is a no brainer.
 
Why buy something you don't need? Why buy something which has an added expense of a timing belt every 100k miles?? Why buy something that has less room to work on the engine? Why buy a vehicle that only has awd? Why buy a vehicle that gets worse gas mileage?

You're right...it is a no brainer.

Ha, thought you were serious for a second. I was going to add, just the V8 sound is worth it. Although the oil filter access is a PITA.
 
Why buy something you don't need? Why buy something which has an added expense of a timing belt every 100k miles?? Why buy something that has less room to work on the engine? Why buy a vehicle that only has awd? Why buy a vehicle that gets worse gas mileage?

You're right...it is a no brainer.

Ignorance is bliss Mike and you sir are blissfully ignorant
 
I have been shopping for a 4th Gen for a few months now. Not in a hurry so taking my time till I find the right one.

I have ruled out the V8 mainly because I don't like the idea of full time AWD. Why did Toyota do that? Wouldn't gas mileage be much better if you could turn it off...like the the V6?

Any V8 owners agree that they would like the option to go RWD? Also, I have read a few posts saying the mpg isn't that much different...maybe so but just hard to fathom how that can be.

For those making it sound like it's ONLY about mpg, maybe I wasn't totally clear because it is not. That is only part of it. In regards to my original post, "...don't like the idea of full time AWD..." I guess I should have elaborated. I basically was wondering how people feel about not being to switch from RWD to 4WD. About all the moving parts, all the time, tight turning, etc.

If I wanted a high mpg, then I agree, wrong vehicle. I am considering the 4R for the occasional boat tow & ski trips, the rest being 2nd family car. So mpg not the end game.

Thanks for all the great feedback so far though. At least now you have confinced me to at least test drive one to see what the infamous torque is like & how it does at slow speed tight turns (as compared to my 4x4 truck).
 
For those making it sound like it's ONLY about mpg, maybe I wasn't totally clear because it is not. That is only part of it. In regards to my original post, "...don't like the idea of full time AWD..." I guess I should have elaborated. I basically was wondering how people feel about not being to switch from RWD to 4WD. About all the moving parts, all the time, tight turning, etc.

If I wanted a high mpg, then I agree, wrong vehicle. I am considering the 4R for the occasional boat tow & ski trips, the rest being 2nd family car. So mpg not the end game.

Thanks for all the great feedback so far though. At least now you have confinced me to at least test drive one to see what the infamous torque is like & how it does at slow speed tight turns (as compared to my 4x4 truck).

A bit more than 140,000 for my 2008, and I drive in some of the worst conditions you can find -- The Sierra Nevada's and California traffic.

In the city, the part-time 4WD works fine; corners, high speed cloverleafs, parking lot 5mph bumpers, etc. We don't get torrential downpours where I go, so asphalt and rain isn't really a concern (and any car can get through 1' of water with a bit of due diligence.

Because I consider my vehicle "high mileage" at this point, we do have to check out how it was maintained. The 4wd has 3 differentials, and I changed the fluid to synthetic at 30,000 and about 60,000 after that (Shell Spirax). Only a monthly basis, you are a supposed to engage the 4wd (which reminds me...) to keep things lubricated, which is easy to forget. I did have a fluid leak one time that went away after I topped of my front diff in about 10,000+ miles (which I believe was because I over filled).

For the snow, a 4WD that engages automatically is a mixed blessing. If you're trucking along, blowing past the chain check point, life is good. BUT when you're approaching that hill, you want to have it engaged and manually engaging it is a good thing. But recognize that if you do engage it, a tight turning radius can be considered bad - which is a negative for the manual engagement (or dropping it into 4-lo). For me, it's good that I can take the tight turns and have the 4wd figure things out, even with 4wd engaged. The only draw back is the engagement time, takes a moment (1-2 seconds, but can be <1 second if the timing is perfect)

For rock crawling (another joy of the Sierras) you're going to drop it into 4-lo most of the time because you're doing straight line crawls. Your turn radius isn't a big deal (no switchbacks where I'm taking my 4Runner) either. BUT if you're trail running AND encounter a rock garden, you may not have the time/opportunity to engage (engage, roll forward, back, etc.) the 4wd. This is also where the part time is great. As things start breaking loose, the 4wd will engage - you may get some wheel spin, but you will have 4wd.

At least that's my opinion. YMMV.
 
For those making it sound like it's ONLY about mpg, maybe I wasn't totally clear because it is not. That is only part of it. In regards to my original post, "...don't like the idea of full time AWD..." I guess I should have elaborated. I basically was wondering how people feel about......all the moving parts......etc.

Well, gas mileage is about the only significant reason, and it only applies to the engine choice, not the full time driveline setup which is a very small contributor.

Not that the following is real important, but for the purpose of explaining why most knocks against the V8 setup are irrelevant, I'll point out that, if anything, the V6 is more complicated and more prone to negligence problems. It has an ADD (automatic disconnecting differential) system in the front that spins all the time and increases wear on various front components. The V8 AWD spreads drive forces around which, on paper, should result in less overall wear. It's well established here that lack of exercise of the transfer case actuator motors is the major contributor to frozen or leaky cases. Exercising the actuators is more easily done in the V8. A small thing, but a plus nonetheless.

The extra moving parts and wear and tear idea doesn't hold any water.
 
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For those making it sound like it's ONLY about mpg, maybe I wasn't totally clear because it is not. That is only part of it. In regards to my original post, "...don't like the idea of full time AWD..." I guess I should have elaborated. I basically was wondering how people feel about not being to switch from RWD to 4WD. About all the moving parts, all the time, tight turning, etc.

There is no problem with tight turning, because of the Torsen center differential.

In a part-time 4WD system, when you put it in 4WD the front and rear driveshafts turn at the same speed. When you go around a corner, the rear wheels cut inside the path of the front wheels, so the rear wheels travel a shorter distance. As a result, the rear driveshaft needs to turn fewer revolutions than the front driveshaft. Since the front and rear driveshafts must turn at the same speed in a part-time 4WD system, it is hard to turn tightly on dry pavement (and potentially damaging to the drivetrain).

But the 4th gen 4Runners are not part-time 4WD. They are full-time 4WD. The center differential allows the front and rear driveshafts to turn at different speeds. Think about what a rear differential does -- it has an input shaft, two output shafts, and allows the two output shafts to turn at different speeds. The center diff does the same thing.

As a result of that center diff, there is no scrubbing when making a tight turn in a 4th Gen 4Runner, as long as the center diff is unlocked. If you lock the center diff, then the front and rear driveshafts turn at the same speed so it behaves like a part-time system.

As for "all the moving parts all the time," what moving parts are you worried about? So the front driveshaft, half-shafts, and front diff are turning. So what? Those aren't exactly parts that tend to wear out quickly. And if you need to accelerate quickly in the rain, like entering a fast road from a parking lot, the truck just goes -- you don't have to worry about spinning your rear wheels as you might in RWD. You never have to ask yourself "should I put it in 4WD or not" -- it already is in 4WD.
 
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