write up: ADD 2wd LOW
- Thread starter snow junky
- Start date
Gerdo
New member
I still don't see any reason that I can't flip the ADD/2wd switch while driving. Think about it. When you are driving along in a stock 4runner, shift the lever into 4Hi, the ADD is actuated. There isn't anything to sincro the Add with the transfer case. Shifting out should be less than no problem.
I was thinking that I wanted to do a "on the jacks" test. But this would not be spinning the front tires when I hit the switch.
The only way is to drive real slow and if there aren't any bad clunks or grinding, try again at a slightly faster building speed each time.
I was thinking that I wanted to do a "on the jacks" test. But this would not be spinning the front tires when I hit the switch.
The only way is to drive real slow and if there aren't any bad clunks or grinding, try again at a slightly faster building speed each time.
Gerdo
New member
I'm not sure what a 3 position switch will give you. This mod only cuts one wire that gets switched with a SPST switch. Also (as spec'd above) will give you 2Hi, 2Hi, 4Hi, 2Lo, 4Lo.
4Running Daily
New member
Found the perfect use.
1st gear in 2WD Low in a drive-through
1st gear in 2WD Low in a drive-through
glenyoshida
New member
I agree. I don't see a reason why it would be an issue to be in 2Lo (while driving forward, ADD disabled) and then to close the switch to go back into 4Lo (while also driving forward, enabling the ADD).
The difference in rotation between the driver's and passenger side axles is dependent on how much drag there is on the intermediate shaft #1 (passenger side axle of the spider gears). The higher the speed the more likely there will be problems with the sleeve being able to engage. Probably why the Toyota computer doesn't allow the ADD to engage at speeds much higher than 50 mph.
I'll have to give it a go when I get around to doing the mod and test it out.
BTW one other reason why this would be a good mod to have is for the unfortunate time where ya might have a front differential fail. Something like blown up spider gears or ring and pinion for example. It can save a lot of trail work to be able to pull the mid shaft on both your CVs (leaving the axle parts in the hub and in the differential) instead of trying to replace a differential on the trail. That allows you to roll out in 2Lo and avoid dropping the diff until you get back home.
If you have a vehicle with an open center differential, then a broken axle can leave you with a non moving rig that is sending all your power to the single broken axle. You would need to put it back into 2Hi to move again but that could cause your transmission to overheat and in many cases your rig would not have enough torque to make it up a steep trail without help from another rig.
Gerdo
New member
Update:
A few weeks ago, while wheeling and easy trail, I gave the system a test.
I have 2Hi like factory. (switch on)
2Hi, lever moved to 4Hi (switch off)
4Hi, lever moved to 4Hi (switch on)
Neutral like factory
2Lo, lever moved to 4Lo (switch off)
4Lo, lever moved to 4Lo (switch on)
Everything worked great.
I also flipped the switch (while in 4LO), and moving, without any unusual noises. The switch put the vehicle in and out of 4wd.
What a great mod. It's awesome to have the low speed control and the low torque even when 4wd is not needed or wanted.
A few weeks ago, while wheeling and easy trail, I gave the system a test.
I have 2Hi like factory. (switch on)
2Hi, lever moved to 4Hi (switch off)
4Hi, lever moved to 4Hi (switch on)
Neutral like factory
2Lo, lever moved to 4Lo (switch off)
4Lo, lever moved to 4Lo (switch on)
Everything worked great.
I also flipped the switch (while in 4LO), and moving, without any unusual noises. The switch put the vehicle in and out of 4wd.
What a great mod. It's awesome to have the low speed control and the low torque even when 4wd is not needed or wanted.
Kraze
New member
I just did this, but hooked it up to a SPDT relay that goes to a OTRATTW switch, with one wire going to 87a, the normally closed terminal, then the other going to terminal 30, the common terminal, so hopefully, when I flip the switch, it will break the connection and I'll have 2wd low, and when the switch is off, everything will be like normal. Anyone see any problems with this plan?
Robb235
Senior Member
Help me out with some of your acronyms; I'm not the most electrical savy guy. SPDT is single pole dual throw. What is OTRATTW?
white_n_slow
Senior Member
Kraze
New member
Thanks for clearing that up, probably should have given the link in my post haha.
My main concern with doing the mod this way, is that the switch is powered, so it can energize the relay. The relay itself isn't hooked up to the battery, or any power source at all, just the switch. It sounds like the wire doesn't carry much current at all, just a signal really, so will the relay be adding any power into that line that it's not supposed to, and will that affect anything?
My main concern with doing the mod this way, is that the switch is powered, so it can energize the relay. The relay itself isn't hooked up to the battery, or any power source at all, just the switch. It sounds like the wire doesn't carry much current at all, just a signal really, so will the relay be adding any power into that line that it's not supposed to, and will that affect anything?
Ol'Blue
New member
The proof is in the pudding guys. We ran a local trail in 2wd Low with the e-Locker locked up. AMAZING and FUN! You get the lower end torque both back wheels turning and the ability to choose what is best for the conditions on the trail. Will be doing this one and also taking another stab at the grey/blue wire mod after running the trail today.
white_n_slow
Senior Member
One question about switches: I have no idea what single post, dual post, single throw, dual throw, etc. actually mean. I want to use an OTRATTW switch for this mod, but I'm confused by all the options. I know Kraze used a SPDT switch, but I would just like to wrap my head around what that actually means.
Toggle switch looks a little booty-fab, IMO, hence the desire for a better switch. I've owned several old junkers with toggle switches for god-knows what... we always called it the "emergency burn down the car switch."
Toggle switch looks a little booty-fab, IMO, hence the desire for a better switch. I've owned several old junkers with toggle switches for god-knows what... we always called it the "emergency burn down the car switch."
Kraze
New member
If you want to do it the way I did, you'll want a SPST switch and a SPDT relay. I wanted it to function like stock with the switch off, that's why I needed the SPDT relay. Let me know if you need any help and I'll do a quick write up for you.
white_n_slow
Senior Member
Sure, I would appreciate a write-up if it's not too much trouble. I guess I'm having trouble understanding how the relay works or why it would be necessary. If I understand the concept correctly (assuming a simple toggle switch): open = front ADD not engaged, closed = front ADD engaged as long as the shifter is in 4wd. Correct?
And is a simple toggle switch like a lot of people in this thread used considered a SPST switch? I'm thinking I might have OTRATTW make me an "ADD" switch.
Kraze
New member
A simple toggle switch is an SPST switch, and will work just as well. The only reason I went with an OTRATTW switch, was because I was already doing 5 other switches, and I had an open spot in my six-position switch holder. And the only reason I used a relay, is because I wanted everything to be like stock with the switch off. Without the relay, the switch would have to be powered and on for everything to be like stock, and off would be the 2wd mod enabled, if that makes sense.
If you don't mind using a simple toggle switch, I suggest going that way. It's not fun wiring up switches and relays haha.
white_n_slow
Senior Member
I just don't like the look of a toggle switch, and the fact that it sticks out seems like it would be more likely to get bumped. DEFINITELY don't like the look of a toggle switch with a big red cover on it 
So does a SPST switch from OTRATTW need power in order to work?
So does a SPST switch from OTRATTW need power in order to work?
Kraze
New member
Hmm, that's a good question. I know it will need power if you want the lights on it to work (obviously), and it would need power if you wanted to use a relay, but if you wanted to just use it as a bare bones switch, well--I'm not sure haha. That would be a question for OTRATTW, or someone else more knowledgeable than me.
