Mods - ATRAC & Locking rear dif in other than 4L
- Thread starter LWN
- Start date
Rokhound21
New member
Following! This mod is high on the priority list
Yamahawarrior89
New member
Did anyone get this to work with just grounding the wire?
I hate to add to this already long thread, but there is some confusion on my part.....
For grounding the blue wire to a switch, that will allow rear locker in 4Hi, correct?
It will not allow rear locker in 2Hi, correct?
For rear locker in 2Hi, another wire (grey?) needs to be grounded via a switch as well. Yes? So does that mean two switches engaged for 2Hi and rear locker, or just one?
Can anyone clarify that for me? All the attached pics are perma-blurry... stupid imgur...
For grounding the blue wire to a switch, that will allow rear locker in 4Hi, correct?
It will not allow rear locker in 2Hi, correct?
For rear locker in 2Hi, another wire (grey?) needs to be grounded via a switch as well. Yes? So does that mean two switches engaged for 2Hi and rear locker, or just one?
Can anyone clarify that for me? All the attached pics are perma-blurry... stupid imgur...
Whippersnapper02
Senior Member
There's a locker mod on TW (Tacoma World). It requires cutting and splicing the 4wd ECU harness. I've done it before on my Tacoma but haven't on my Runner just yet.
LWN
Member
Shouldn't be any problem working in 2H. The point of the mod is to trick the ECU into thinking you're in 4L so it'll allow the ATRAC and rear locker to engage.
I've been using this mod for years an it works well - the only issue I have is that if you go too fast with it engaged, the CEL comes on and some 4wd dash lights start flashing, although it doesn't seem to impede the action of the locker or ATRAC. I have to assume that it throws a trouble code for going too fast when the ECU thinks the truck is in 4L. It's annoying, but after a handful of ignition cycles/miles, they turn off by themselves. I suppose clearing the codes manually would probably work as well.
In any case, this mod has gotten me through some incredibly tough spots in mud and sand.
I've been using this mod for years an it works well - the only issue I have is that if you go too fast with it engaged, the CEL comes on and some 4wd dash lights start flashing, although it doesn't seem to impede the action of the locker or ATRAC. I have to assume that it throws a trouble code for going too fast when the ECU thinks the truck is in 4L. It's annoying, but after a handful of ignition cycles/miles, they turn off by themselves. I suppose clearing the codes manually would probably work as well.
In any case, this mod has gotten me through some incredibly tough spots in mud and sand.
Hello!
I have an SR5 and very interested in this mod for getting out of muddy situations. Don't have a locking differential but ATRAC activation in 2H would be enough to get traction. I noticed the CEL issue mentioned. Are we sure it's speed related? I was wondering based on the diagram if the 4WD ECU expects both the 4H and 4L inputs to be grounded rather than just the 4L switch. Any thoughts?
I have an SR5 and very interested in this mod for getting out of muddy situations. Don't have a locking differential but ATRAC activation in 2H would be enough to get traction. I noticed the CEL issue mentioned. Are we sure it's speed related? I was wondering based on the diagram if the 4WD ECU expects both the 4H and 4L inputs to be grounded rather than just the 4L switch. Any thoughts?
LWN
Member
So in my experience using this mod for many years, flipping the switch and/or engaging the locker and/or ATRAC do not automatically flip the CEL on, it takes some time using it in that mode. So I'm not completely sure what feedback the ECU is getting that it doesn't like, I'm just guessing that it was sensing excessive speed while it thinks I'm in 4L. I may misunderstand you, but I don't think you'd want to ground both 4L and 4H at the same time as that would surely cause a confused ECU.
Hey LWN:
Thanks for the quick response! So in all your years of using it, you have seen no adverse effect? I am currently looking at adding a e-locker for the back and SoCal quotes are coming in at around $2,400 for an Eaton rear locker. The ATRAC in 2H mod seems a much cheaper alternative
1000MPH
Senior Member
How hard is ATRAC on the drivetrain? I don’t really notice when using it but it looks a little abrupt in videos. Wondering if that is why there’s a speed limit.
I’ve found regular old traction control in 2wd is often enough until wheels come off the ground or things get start to get steep.
I’ve found regular old traction control in 2wd is often enough until wheels come off the ground or things get start to get steep.
LWN
Member
Hey LWN:
Thanks for the quick response! So in all your years of using it, you have seen no adverse effect? I am currently looking at adding a e-locker for the back and SoCal quotes are coming in at around $2,400 for an Eaton rear locker. The ATRAC in 2H mod seems a much cheaper alternative
Not at all - there's really no possible mechanical adverse effects that I'm aware of as long as you don't use it on pavement. The annoying thing is the CEL and a few other of the Traction Control lights will come on, but they go off after a few miles/ignition cycles, and I could probably force them off by clearing codes.
Honestly I don't know why Toyota limited ATRAC and the locking rear diff to 4L only. That's fine for rock crawlers but where I live it's mud and sand, and you need RPM's to get through mud.
ATRAC is nice depending upon the situation but I'd say it's not a replacement for a rear locker. The way it works is when a wheel starts to spin it applies brakes to that wheel and redistributes power to the wheels with traction. In sand that's a very good thing. In mud I'm not sure that's always a good thing since I need some amount of wheel spin on every tire to keep my tires clean and moving forward. It's an electronically simulated locker of sorts but not quite the same thing. You'll hear it when it works - it makes the same sound the antilock brake system makes when you're starting to skid.
Still, I always use the locker and ATRAC together when I'm in a tough situation. I'd say give it a shot and see how ATRAC alone works for you.
LWN
Member
It's a wear on the brakes for sure. With a locker you have 100% of your power going to both tires. With ATRAC you're basically pumping the brakes on the wheel that's spinning in an effort to redirect power to the wheel on the other side of the differential. Still it does work but not as efficiently as a locker. Other than your brakes, I can't see how it would have an effect on the drivetrain.
It's the same system used for your traction control/antilock brakes, and those can and do engage at any speed. It definitely makes some noise when the ABS system kicks in though.
Jono.ful
New member
Yep, doesn't take too long to overheat to the point where atrac won't function. You'll get all the abs system warning lights until it cools down.
The Last Boy Scout
New member
Quick question
I've seen several folks, in this thread, saying that this mod has worked well. But unless I missed something, it appears they all have 2014 or older 4Runners. In certain situations, I'd like to be able to use the rear locker or maybe ATRAC when in 4 high. I have a 2018 4Runner TRD OFF ROAD and I'm wondering if this mod is doable on my vehicle. And if so, is it basically achieved in the same manner? Any input or clarification would be greatly appreciated.
I've seen several folks, in this thread, saying that this mod has worked well. But unless I missed something, it appears they all have 2014 or older 4Runners. In certain situations, I'd like to be able to use the rear locker or maybe ATRAC when in 4 high. I have a 2018 4Runner TRD OFF ROAD and I'm wondering if this mod is doable on my vehicle. And if so, is it basically achieved in the same manner? Any input or clarification would be greatly appreciated.
chrisridebike8
Member
I know without modding, since you have a TRD OR, you can use MTS Mud/Sand in 4Hi and that will give you some of the atrac functionality. It allows the most wheelspin but still uses the brakes a little to distribute the torque. Make sure you are slow enough for the system to allow you to engage it (think it’s like 7 mph…basically just stop) and when you press the button, the knob has to be all the way to the left (meaning if you had Mogul or Rock selected the previous time, it will try to select that again when you activate MTS, so tell it Mud/Sand, and THEN activate it).
Sent from my iPhone using Tapatalk
The Last Boy Scout
New member
Thanks for the quick reply chrisridebike8. I'm up to speed on what you said and have often used the MTS Mud/Sand in 4Hi while off roading. That said, I would like to be able to engage the rear locker in 4Hi, in certain situations. So, I was trying to get confirmation that the wiring and method of tapping in to the (correct) wire, going to a switch, and then to ground was essentially the same procedure on my 2018 as folks have done on their 2015 and earlier 4Runners. Again, thank you.
