4 runner center differential lock (1 Viewer)

[rc51kid]

I am new to 4WD so maybe I just don’t understand some things. But what is the point of a center differential on a 4wd? I know that a regular diff (on a axel) lets the L and R wheels turn different speeds while turning corners. But why would you want the front wheels turning different speeds than the rear wheels? Also, I know how bad open diffs are in low traction. Does the same thing happen with front and rear diffs? If the rear end is lifted off the ground would the front loose power through the diff?

I this is my real question. I know that some of the LCs have locking central differentials. Is this necessary and do the 4runners have it? is there a way to add this feature?

 

[raydouble]

I am new to 4WD so maybe I just don’t understand some things. But what is the point of a center differential on a 4wd? I know that a regular diff (on a axel) lets the L and R wheels turn different speeds while turning corners. But why would you want the front wheels turning different speeds than the rear wheels? Also, I know how bad open diffs are in low traction. Does the same thing happen with front and rear diffs? If the rear end is lifted off the ground would the front loose power through the diff?

I this is my real question. I know that some of the LCs have locking central differentials. Is this necessary and do the 4runners have it? is there a way to add this feature?

I'm not sure exactly but I think all years limited's and the 01-02 4runner have multimode 4wd system. It's easy to identify, look for the push button on the side of the transfer case shifter.

The center diff is unlocked when in 4wd high, for push button 4wd (awd) on pavement, so the front wheels can turn at different rates than the rear wheels.

The center diff is locked when in 4wd low to act as a conventional 4wd system.

 

[d0ubledown]

if you under stand how axle diffs let L&R axles (wheels) spin at different speeds during a turn, then the same applies to a center diff, only that it allows the front & rear driveshafts (to their respective diffs) to spin at different speeds, allowing you all wheel drive with differentiation in the diff to allow for turning without binding the drivetrain. once that tcase differential is locked, it becomes a traditional 4wd where the front & rear driveshafts spin at the same speed. this will bind the drivetrain on high traction surface in turns since the differentiation is now gone by locking the ctr diff.

in a traditional part time 4X4 system where there is a 2H, 4H, and 4L, the 4H & 4L engages the front driveshaft in the tcase so that both front & rear driveshafts are spinning at the same time. 96-99 have this traditional part time 4X4. the 00-02 are the only ones in the 3rd gen 4runner applications with the multimode setup.

you cannot add this feature without swapping out the tcase itself, along with all the sensors and ECU that controls the multimode system. not worth it nor is it necessary on a vehicle. imo, it just adds to more problems (which it has on these certain 4runners). the landcruiser setup is all wheel drive, all the time. there is no oem part time 4X, at least not in the NA market.

the multi mode operates in:

2H (high range, rear wheel drive)
4H open (high range, all wheel drive)
4H locked (high range, even power split to front/rear)
4L locked (same as above in a lower range)

confused yet?

 

[Happy Trails]

Thanks, I've been wondering about this center diff ever since I've had my Ltd. You have done a much better job than my manual.

 

[brian2sun]

The multi-mode system wasn't available at all on '96-98 4runners. Then it became standard equipment on the '99 and '00 Limiteds only, but not the SR5s or Sport/Highlanders for these years. Then it was made standard for all 4x4 '01 and '02 4runners.

 

[raydouble]

The multi-mode system wasn't available at all on '96-98 4runners. Then it became standard equipment on the '99 and '00 Limiteds only, but not the SR5s or Sport/Highlanders for these years. Then it was made standard for all 4x4 '01 and '02 4runners.

Thanks Brian, I was wondering about that.