2010 SR5 doesn't have rear differential lock?

[quhongjun]

I just noticed that Trail Edition has another feature "Locking rear differential, Multi-terrain select and Crawl Control" which is not showing for SR5.

I know that "crawl control" is specific to Trail edition, however I don't understand why SR5 doesn't have rear locking differential. Since SR5 and Trail don't have center differential locking too, does that mean the SR5 only has front differential locking?

:AK47:

 

[Clemsonfan15]

No 4runner has ever been offered from the factory with a front locker.

 

[M1911]

I just noticed that Trail Edition has another feature "Locking rear differential, Multi-terrain select and Crawl Control" which is not showing for SR5.

I know that "crawl control" is specific to Trail edition, however I don't understand why SR5 doesn't have rear locking differential. Since SR5 and Trail don't have center differential locking too, does that mean the SR5 only has front differential locking?

No. None of the 4Runners have a locking front diff. The TE and SR5 have a part-time 4WD system -- they don't have a center diff. When in 4WD, the front and rear driveshafts rotate at the same speed.

 

[quhongjun]

No. None of the 4Runners have a locking front diff. The TE and SR5 have a part-time 4WD system -- they don't have a center diff. When in 4WD, the front and rear driveshafts rotate at the same speed.

thanks you guys for the explanation. I still can't understand: if it doesn't have front or rear differential lock, how can it deal with the situation when one wheel loses traction and spinning? Just like this video shows:
YouTube - Toyota 4Runner Diff. Lock Demonstration

 

[tcpoob]

the ride in the video was modified to add a front locker, it looks. just because it doesn't come from factory doesn't mean you can't get it. how does that sound?

thanks you guys for the explanation. I still can't understand: if it doesn't have front or rear differential lock, how can it deal with the situation when one wheel loses traction and spinning? Just like this video shows:
YouTube - Toyota 4Runner Diff. Lock Demonstration

 

[M1911]

thanks you guys for the explanation. I still can't understand: if it doesn't have front or rear differential lock, how can it deal with the situation when one wheel loses traction and spinning? Just like this video shows:
YouTube - Toyota 4Runner Diff. Lock Demonstration

With a part-time 4WD system (or a locked center diff as you can do with the Limited), both the front and rear driveshafts will turn at the same speed. However, open front and rear diffs do not balance torque from side to side. So if both a front and rear wheel have no traction (e.g., on ice), then you won't go anywhere.

There are several solutions to this problem:

a) limited slip rear diff will try to transfer torque from one rear wheel to the other, but won't handle the situation where one has 0 grip (wheel on ice or in the air) unless you left foot brake.
b) locking rear diff will cause both rear half shafts to turn at the same speed.
c) ATRAC differential braking will try to transfer torque from one rear wheel to the other.

Of the options above, I'd rank b as the best, followed with a, and the c.

In the case of the video shown, it looked to me as though only one wheel (right front) was without traction. The only way you would get stuck in that situation is if you had an open center diff. You would not get stuck in either a part-time 4WD (e.g., SR5 or TE with ATRAC somehow disabled) or a proper full-time 4WD (e.g., Limited either locked or unlocked). In any case, ATRAC would help.

Yes, a locking rear diff is best. Do you need a locking rear diff? What sort of offroading do you think you will be doing? I take my '03 Limited 4WD on the beach every year. It has an open rear diff. I air down lock my Torsen center diff on the beach. I've never come close to getting stuck.

Is the 5th Gen TE better offroad than the 5th Gen SR5? Sure. Do you need that extra capability? Only you can answer that, but I would suspect that most folks don't.

As for a locking front diff, I believe the only vehicles currently sold with a locking front diff are the Wrangler Rubicon and the Mercedes G500.