Mystery button on my 2001 Limited 4Runner dash

I don't have my user manual, not really sure if I ever had one, bought this 2001 back in ~2010...

But I never thought much of this button before, and I've taken my 4Runner off-road in 4WD plenty of times, mostly at the beach, but it works great. Just a pushbutton engagement on the 4H-4L shifter to put it into 4WD.

Initially I thought maybe it engages a rear diff locker, but checking under the vehicle, there is no locker hardware on the rear diff.

Anyone with a Limited recognize this button and know what it does? The symbology on it made me think it had something to do with 4WD, but maybe it's for disabling traction control? Not sure, could use some help!

Thanks in advance!

 

It's for center diff lock.

 

It's on all 4x4 4Runners for 2001-2002. I have it on my SR5.

 

Yep, you have a lockable center limited slip differential you can use in any conditions including on-road.

Just not when locked.

 

Thanks, I feel a little embarrassed I didn't know my 4Runner had that "feature". Not sure how that'll help me off-roading other than I'll need to make sure it's "locked" from now on, would rather have the locking rear diff, like my 2022 Taco features.

 

It really is a great four-wheel drive system, it's funny how it's more advanced than the one they offer now.

If I recall correctly, they discontinued the rear locker availability in 2000, 2001+ got ATRAC instead.

 

I'm guessing that the ATRAC must have been viewed as better all-around solution to improving traction, both on-road and off-road, but when I was into hot-rods (still have a 98 Trans Am), I always viewed any kind of brake upgrades as things that slow me down, not make me go faster! And so that's the feel I get with ATRAC as well, the computer wants to apply brakes to spinning wheels to improve traction for the non-spinning wheels, whereas the locker is just brute force GO power.

The locker rear ends are still sought after very highly, kinda like the superchargers and hood scoops are still.

 

I agree. There are some people that will tell you that ATRAC is better than dual lockers, but I disagree for the same reason that you stated. Anything that works by engaging the brakes is going to slow your forward progress.
That's cool you still have your T/A, I have a 2000 Formula.

 

ATRAC's main merit is being cheaper to produce once the brakes got ABS and are fully computerized such that they can be independently actuated. Mechanical limited slips and lockers cost extra. ATRAC just required a circuit to control brake pressure on each wheel. The engine output is already moderated by the ECU.

 

Costs whom?

It only "costs" Toyota more if they were to throw a rear locker in for free, but I (and I'm sure lots others) would have gladly paid a little extra for a rear locker option if it was offered!

 

I think the long-time trend of choosing traction control (and related) over mechanical differentials for mass-market vehicles is generally a good choice from the manufacturer.

They get acceptable-to-solid performance (depending) and don't have to spend the money adding another option to a vehicle.

For folks like us who know/might care, they can say "pay more to option it!" if it's available or assume those who care enough will either go get one installed anyway or buy a different vehicle.

I once thought it'd be cool if my dad optioned the rear limited-slip differential option when he bought his RAV4 years ago but since then, it hasn't really been in any situations where that would have came in handy. (other than one time I intentionally put it up on two wheels)

The take rate (or alternatively, how many Toyota decided to make) was not high for that $1-2k option and despite being available in the RAV4, Highlander, RX, it went away the moment stability/traction control showed up. They don't have to worry about any stability/traction control + LSD programming that way too.

More recently, I read that Ford threw in a rear torsen LSD into the Explorer Timberline, but I haven't seen much difference in testing videos online.

 

Unlocked and the 4wd in and you're in full time 4wd. Locked and the 4wd button in you are in par time 4wd hence the X in the center of the vehicle.

 

Umm... My 2022 Tacoma TRD Off Road has both a rear locking diff AND the ATRAC, as well as MTS! I can count on one hand how many times I've used the MTS, and probably NEVER really needed it any of those times, but it sure is nice to know it's there in case I ever do need it, and no it doesn't cost Toyota anything to add that feature, because customers paid for it by choosing that packages that include it.

I think more likely Toyota made a mistake in removing the rear locker feature in these 4Runners, and now that they want to be seen as a serious player with the off-road, overlanding customers, it was added back.

Just my $0.02 though.