General Question on Locking Rear Diff 4Runner

[Paul2660]

I am curious why Toyota took away the locking rear Diff on the 4th gen 4 runner. Not sure on the 3rd Gen if it had it or not.

The reason I ask, is that Toyota's electronic design on the locking rear diff is somewhat unique. I can remember on the 1993 Landcruiser what Toyota brought out the sep locking front and read diff's and what a huge deal that was for 4WD design. This system is one of the most sought after parts from a wreaked Landcruiser. If you don't have this setup, many use the air poppers to get the same sep locking diffs.

I know that the Tacoma has this as an option and I have been told the Tundra and Sequoia all have the locking rear as an option.

I have always felt that the 4runner was a very adept off road truck and was surprised to see that the locking rear diff option had been taken out.

I understand about the locking center diff, and limited slip, however being able to lock the read can be most important depending on the traction needs.

Was Atrac the answer for this? And if a truck has Atrac can it thus not have a locking rear diff?

I would appreciate others thoughts

Paul C

 

[spud72]

I find it interesting too that they put a LSD in the 2WD, but just leave it to the ATRAC with the open diff in the 4x4.

 

[Paul2660]

LSD 4WD

The 4WD has the LSD and when in 4Hi, you automatically have the Torsen working.

And like you point out, you can lock the center diff. Which gives you what I have always called old fashion 4WD, in that your front and rear wheels will turn in different radius's, thus you are only supposed to use this off road or on a surface that will also slippage, (snow, wet road etc).

What is so impressive about a full locking rear diff is when one side of the truck is on a slick surface. The best demonstration I have seen recently is a Auto Week TV review of one of the new Chevy's. They use a boat ramp, where you have one side concrete and on the other rollers. They first use a LSD on this ramp and it won't make it, especially if they stop on the rollers. Then they switch to a truck with the locking diff on the rear. No problem as the fully locked rear will get plenty of traction on the concrete side and go right up the ramp.

I assume that Toyota's Atrac would assist here since you would be hopefully braking on the side that has the rollers, but still to a layman like me, the pure and simple locking rear is a better solution. I have yet to get into a situation where I have engaged Atrac.

Paul C.