sorta related, but how strong are the rear axles in our 4R's? how you they compare to like a Dana 44? this is a good mod, but you do need to be a little more careful with the extra wheel speed in 4Hi and suddenly "catching" traction at one rear wheel. it could put a lot of stress on the rear end.

I guess you could, but I wouldn't. The one quirk of this setup is that if I forget to flip the switch off before I turn the ignition off or before I put it back in 2WD, sometimes the check engine light will come on. It doesn't seem to affect the running and it does go off eventually, but it's annoying. And yes, the 4L light does come on when I engage the switch, even though the lever is in 4H, because the 4WD CPU has been fooled into thinking the lever is in 4L. Other than the occasional check engine light issue, I've been using it for a year now and it's been working great.

So are you able to lock in 2wd???

do you know where the wiring is for the rear locker button?

would it be possible to tie this mod into the locker button itself?

Honestly I've never tried locking the rear diff in 2WD. But no, this mod really has nothing to do with the wiring for the locker switch itself. The 4WD ECU is programmed to not allow the locker switch to engage the locker unless you're in 4L, so the only way around that is to fool the ECU into thinking you're in 4L when you're in 4H. That's what the mod does.

^I understand that, but was wondering if its possible to do your mod, but wire it in a way that it engages when you hit the locker switch, so it is essentially a one button process. are you still able to use 4Lo with the switch off? or do you have to turn it on in order to use 4Lo?

Good question - I'm sure it can be done, via an installed relay if necessary, but I haven't looked into it. And yes, with my switch off, everything works normally. The switch doesn't affect the mechanical engagement of 2WD, 4H or 4L, just whether or not the ECU thinks you're in 4L.

Has anyone one this on a non trail edition SR5? I dont see any reason it wouldnt work?

Except that the "non trail edition SR5" doesn't have a locker.

I would guess that Toyota's reason for not making the rear diff lockable in 4H relates to the speed you are operating the vehicle at while in 4H. If you lock the rear differential then you loose the ability for the wheels to turn at different rates of speed. This can be especially bad while making turns on high traction surfaces.

I only have atrac on my limited, but my tacoma had a locking rear diff which I mainly used on steep hill climbs in 4L. We don't really mud out here unless you want to bury your truck.

Before you do this you should keep in mind that at higher speeds than 5mph you should minimize turns, unless you want axle damage. Plus you really should have good tires on the 4runner first.

There is another reason they are blocked in 4H. The traction system works by applying brakes to spinning wheels so power is transfered to the wheel(s) with traction. Do this at a high rotational speed and the sudden change in power transfer from the spinning wheel to the one getting traction can do nasty things to the axles, half-shafts, etc. This was encountered with some more-money-than-brains-yuppies that bought Hummers, got stuck and hit the brake pedal to get traction while spinning the wheels like crazy.

That said, I plan on this mod with the knowledge that I have to be careful and should disable ECU activated traction control.

Any luck of this mod working on the Limited models? ATRAC will ONLY work in 4L right? ATRAC essentially acts as an electronic diff by applying brakes to the spinning wheel thus enabling the stopped wheel to turn right? so if we mod it to work with 4H then we would have those advantages without needing 4L! and not worrying about the rear locker being an issue.. ATRAC is essentially electronically doing that from what i gather.. any input please share!

Ok, not trying to highjack this page. What is the switch/ button on the lower row on the left side?

From the owners manual......

Attached Files

Doc1.doc (93.0 KB, 1132 views)

If you are talking about the switch lowest in the pic then you should probably re-read the thread as you missed the whole point.

-bh

To be honest, I checked my manual and it is not in there. Thanks for the info.