question about part-time 4WD on Trail Edition

[JB.]

I might quibble with your technical explanation but the net effect and advice of locking the center before getting into mud is certainly right on.

But remember, ATRAC only works on the SAME axle. It does not coordinate b/w the axles.

ATRAC does effect the opposite front or rear axle. In your example, any ATRAC intervention on the front will be transferred across the center differential to the rear. In the case of the Torsen diff, it will be transferred and multiplied by the torque bias ratio.

if your whole front axle is deep in mud/snow/ice...you will be stuck if you did not lock the center diff. Why? ATRAC on the front axle will NOT operate because as far as it is concerned, the two front tires are spinning at the same speed

you MAY be stuck and it MAY not operate to the degree that you wish. If you're sitting there stuck, spinning the front wheels in mud (ignoring VSC), ATRAC will be engaging at some point.

both tires on the front axle will spin freely like nothing has happened. This would mean ZERO traction on the front axle in the Torsen center diff eyes. So, it will send all torque to the front axle...and zero to the rear axle

It won't end up sending torque to the axle with the least traction. It's still sending more torque to the rear - multiplied by the torque bias ratio - it just might not be enough torque to get unstuck.

 

[Quentin]

I don't know if there's a real world difference, but I do know that the fuel economy rating for both is 17 city/22 highway.

Limited does get 245 tires instead of 270 tires like the TE and SR5. It gets narrower wheels as well. I'm of the opinion that decision was made for fuel economy reasons... unless narrow tires is the new thing for luxury SUVs.

 

[JB.]

I am surprised so many replies here. I am really appriciate all your guys help. Some answer/discussing seems beyond my knowledge. Anway, can anybody tell me how Trail Edition to be operated when facing mixed surface and tunning? Should I keep switch between RWD and 4WD? Can I do this when I am driving? Is there any difference when my speed hits 80miles and 40miles?

It just comes down to your priorities. It simpler to just think of the Limited full-time 4WD as a luxury. That's mostly what it is.

Do you wish to give up that luxury for the things you like in the Trail or not. In the Trail you would drive in 2WD, even in mixed conditons only using 4WD when moving in 2WD was too difficult. You could switch to 4WD while moving. If you can go 80or 40mph, you don't need to be, and shouldn't be in part-time 4WD.

 

[DocMT]

Limited does get 245 tires instead of 270 tires like the TE and SR5. It gets narrower wheels as well. I'm of the opinion that decision was made for fuel economy reasons... unless narrow tires is the new thing for luxury SUVs.

You might be right about the reasons for the narrow wheels & tires. But I'm also speaking from my own experience.........I run my 4Runner in fulltime 4wd throughout the entire winter and switch it back to 2wd in for the spring/summer/fall months. I don't see any difference in my calculated fuel economy when I'm in fulltime 4wd compared to when I'm in 2wd. It's virtually the same, but for some reason it gets about 1 mpg higher in July & August than any other months. Not sure why though.

 

[harper7]

Since ATRAC only works in 4LO with the center diff locked, it's sort of a moot point isn't it?

Also, are you sure that ATRAC only works on the same axle? I would've guessed that the ECU would monitor slippage on all four wheels and modulate accordingly. But just a guess.

On the 4th gen 4Runner ATRAC works in 4HI or 4LO and with or without the center diff locked.

And ATRAC is what controls torque delivery side-to-side. If the front left wheel spins, ATRAC brakes that wheel, which sends torque to the front right wheel. Same is true for the rear axle. The center diff controls torque delivery front and rear. When you lock the center diff, you're making 50% of the torque go to the front axle and the other 50% to the rear axle. Put it all together and you have torque being sent to both the front and rear (via a locked center diff) and from side-to-side via ATRAC. It's a great system.

A-TRAC and TRAC are 2 different things on the 5th Gens and have 2 separate overhead switches on my Limited.
Since this is the 5th Gen sub forum and the question was about 5th Gens maybe we should stick with them.Confusing enough without you giving info on how older 4Runners work.

Straight out of the Owners Manual .....pg 226 A-TRAC is activated by an over head switch only in 4LO and only less the 4mph. A yellow light stating A-TRAC lights up on your dash telling you A-TRAC is activated.

In the Owners Manual ....pg 253 Disabling TRAC (4WD models) Quickly press push and release the TRAC off button to turn Trac off . A yellow light comes on you dash that says TRAC OFF.

In the Owners Manual ....pg 254 To turn the TRAC and VSC systems off....press and hold the TRAC OFF button for 3 seconds or more. Pressing it again turns them back on. You will get the TRAC OFF light and the truck pic with squiggly lines underneath it lights on the dash. Canada models will get a TRC OFF light.

I have the first revision of the owners manual so they might be on different pages in yours . But they should still be under the Chapter"USING OTHER DRIVING SYSTEMS" There is alot of other warnings and advice to read in there on the 4WD systems.
People really need to .....:rtfm:
I tested the systems with the switches offroad and they worked as advertized.As stated before A-TRAC ON in 4LO and keep the rpms about 2 grand and it feels like your in a tank.Use your S mode shifter to keep the rpms where you want them.

What's the difference in the two?

TRAC
Toyota’s Traction Control System continuously monitors the wheels whenever the vehicle accelerates. As soon as it detects that one or more drive wheels is starting to spin, it applies the brakes to the wheels and controls engine output to help the wheels better adhere to the road surface.

A-TRAC
More aggressive form of TRAC & for 4WD OFF ROAD use only. Does the same thing as TRAC except it doesn't cut/control engine throttle. Instead, it transfers torque from slipping/spinning wheel(s) to non slipping wheel. This gives added traction & forward momentum to overcome Off-road obstacles. This can only be engaged while in 4LO.

BTW JED you never mentioned what year your 4Runner or if you even own one in your 500+ opinionated post since last month...I read them since your my hero.Did you buy a new 5th? Your giving so much advice on them it looks like you gave in.And you still hav'nt learned how to multi-quote after all this time??.....that's what gave you away.lol:hello:

 

[Quentin]

You might be right about the reasons for the narrow wheels & tires. But I'm also speaking from my own experience.........I run my 4Runner in fulltime 4wd throughout the entire winter and switch it back to 2wd in for the spring/summer/fall months. I don't see any difference in my calculated fuel economy when I'm in fulltime 4wd compared to when I'm in 2wd. It's virtually the same, but for some reason it gets about 1 mpg higher in July & August than any other months. Not sure why though.

I see a 10% mpg swing just from winter to summer based on winter gas and it taking longer for the engine to reach normal operating temps. You must live somewhere that doesn't get ****ty gas from late Nov ~ Mar. All of my cars have showed this trend.

 

[DocMT]

I see a 10% mpg swing just from winter to summer based on winter gas and it taking longer for the engine to reach normal operating temps. You must live somewhere that doesn't get ****ty gas from late Nov ~ Mar. All of my cars have showed this trend.

I don't know, all I can say is that my mileage stay remarkable consistent, and only seems to vary in the hottest summer months. I don't know why, that's just the way it is.

 

[Fareastplaza]

I finally test drove an trial edition today. I just test it on dry pavement. On the road, I turn 4h, and I didn't see any problem. Most turn on the road I couldn't feel any difference like change lane, turn left/right at intersection. The road is pave and dry. I also tried very sharp turn on an empty parking lot with dry surface. With the most sharp turn, I do feel spinning and can hear tires be forced to scrach the ground. It's actually lighter shaking compare to using wrong gear when you drive standard. Dealer told me, even you doing this, it still won't hurt anything unless you do it all the time for a very long time.

I am not sure if he is right. Is there anybody here driving trail edition or sr5 have this doing many times and no harm to the car at all?

 

[SeattleMike]

I finally test drove an trial edition today. I just test it on dry pavement. On the road, I turn 4h, and I didn't see any problem. Most turn on the road I couldn't feel any difference like change lane, turn left/right at intersection. The road is pave and dry. I also tried very sharp turn on an empty parking lot with dry surface. With the most sharp turn, I do feel spinning and can hear tires be forced to scrach the ground. It's actually lighter shaking compare to using wrong gear when you drive standard. Dealer told me, even you doing this, it still won't hurt anything unless you do it all the time for a very long time.

I am not sure if he is right. Is there anybody here driving trail edition or sr5 have this doing many times and no harm to the car at all?

It's not okay to do all the time. You shouldn't have been allowed to do it on a test drive at all. Buy the Limited if that is how you intend to drive a 4Runner.

 

[JustLeft]

Time to get a new dealer! I just bought a TE and hope that it was never near your dealer's lot. If you want that, I agree with the earlier reply, buy a Limited.

I finally test drove an trial edition today. I just test it on dry pavement. On the road, I turn 4h, and I didn't see any problem. Most turn on the road I couldn't feel any difference like change lane, turn left/right at intersection. The road is pave and dry. I also tried very sharp turn on an empty parking lot with dry surface. With the most sharp turn, I do feel spinning and can hear tires be forced to scrach the ground. It's actually lighter shaking compare to using wrong gear when you drive standard. Dealer told me, even you doing this, it still won't hurt anything unless you do it all the time for a very long time.

I am not sure if he is right. Is there anybody here driving trail edition or sr5 have this doing many times and no harm to the car at all?

 

[Hawkdog21]

i feel bad for whoever is getting that TE

 

[sandcrawler]

my thoughts exactly. WTF?!

 

[FlyNavy]

i finally test drove an trial edition today. I just test it on dry pavement. On the road, i turn 4h, and i didn't see any problem. Most turn on the road i couldn't feel any difference like change lane, turn left/right at intersection. The road is pave and dry. I also tried very sharp turn on an empty parking lot with dry surface. With the most sharp turn, i do feel spinning and can hear tires be forced to scrach the ground. It's actually lighter shaking compare to using wrong gear when you drive standard. Dealer told me, even you doing this, it still won't hurt anything unless you do it all the time for a very long time.

I am not sure if he is right. Is there anybody here driving trail edition or sr5 have this doing many times and no harm to the car at all?

ygbfsm!

 

[DaveS]

I think a lot of people probably want to know who this dealer is so they can afford them at all costs. Allowing that on a test drive is irresponsible - what next - handbrake turns or perhaps testing out what the max rpms really are ?

 

[JustLeft]

I think a lot of people probably want to know who this dealer is so they can afford them at all costs. Allowing that on a test drive is irresponsible - what next - handbrake turns or perhaps testing out what the max rpms really are ?

I think you meant avoid them! Damn spell checker....

 

[DaveS]

Oops - no spellchecker on Tapatalk.. Freudian slip perhaps?

 

[JustLeft]

Oops - no spellchecker on Tapatalk.. Freudian slip perhaps?

Great program. That's what I use. When typing on the iPhone I get auto correction. Your right though, no one in their right mind could 'afford' to shop there. Just hoping that no one test drove my TE that way!

 

[Ryan_S]

I finally test drove an trial edition today. I just test it on dry pavement. On the road, I turn 4h, and I didn't see any problem. Most turn on the road I couldn't feel any difference like change lane, turn left/right at intersection. The road is pave and dry. I also tried very sharp turn on an empty parking lot with dry surface. With the most sharp turn, I do feel spinning and can hear tires be forced to scrach the ground. It's actually lighter shaking compare to using wrong gear when you drive standard. Dealer told me, even you doing this, it still won't hurt anything unless you do it all the time for a very long time.

I am not sure if he is right. Is there anybody here driving trail edition or sr5 have this doing many times and no harm to the car at all?

 

[sandcrawler]

I finally test drove an trial edition today. I just test it on dry pavement. On the road, I turn 4h, and I didn't see any problem. Most turn on the road I couldn't feel any difference like change lane, turn left/right at intersection. The road is pave and dry. I also tried very sharp turn on an empty parking lot with dry surface. With the most sharp turn, I do feel spinning and can hear tires be forced to scrach the ground. It's actually lighter shaking compare to using wrong gear when you drive standard. Dealer told me, even you doing this, it still won't hurt anything unless you do it all the time for a very long time.

I am not sure if he is right. Is there anybody here driving trail edition or sr5 have this doing many times and no harm to the car at all?

your salesman is an idiot. you need to buy a Limited.

it would be a nice gesture to whomever buys that Trail if you secretly slipped a note behind the 4WD placard on the drivers' sun visor (which, ahem, spells out how to use the system properly) detailing that if future issues arise it may be due to dealer abuse pre-purchase.

and seriously, just buy a Limited.

 

[Fareastplaza]

your salesman is an idiot. you need to buy a Limited.

it would be a nice gesture to whomever buys that Trail if you secretly slipped a note behind the 4WD placard on the drivers' sun visor (which, ahem, spells out how to use the system properly) detailing that if future issues arise it may be due to dealer abuse pre-purchase.

and seriously, just buy a Limited.

yes, I decide to buy Limitied. When I test drove the Trail Edition, I also get a issue. When I drive it on 4WHi, I am on the road. The sales told me you can switch back and force between 4WH and 2Wh on fly. I tried, yes, I swiched back to 2Wh, but for what ever reason, I can't switch back to 4WH. The dealer can't explain why. So, I think Trail Edition is just not the one I want even I like it's looking.