Electrically disconnecting the front Diff - ADD models only

Re: Electrically disconnecting the front diff - SR5 only

Postby martynvella on Wed, 09 Mar 2016 6:09 +0000

Here is another what if question, and the only reason I have not done this mod without incorporating a speed protection circuit.

IF the switch is in L2 and the vehicle is under load , say the boat ramp scenario, rear wheel starts spinning and driver hits the switch with the driveline at speed and under load, would the ADD try to engage and damage the spline?

Or does the ADD ecu already have a speed sensor forcing you to bring the driveline to a rest before it engages.
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Re: Electrically disconnecting the front diff - SR5 only

Postby Batman on Wed, 09 Mar 2016 6:43 +0000

martynvella wrote:Here is another what if question, and the only reason I have not done this mod without incorporating a speed protection circuit.

IF the switch is in L2 and the vehicle is under load , say the boat ramp scenario, rear wheel starts spinning and driver hits the switch with the driveline at speed and under load, would the ADD try to engage and damage the spline?

Or does the ADD ecu already have a speed sensor forcing you to bring the driveline to a rest before it engages.


Martyn I am not being critical of your question, or you for asking it, so please take my answer with a grain of salt...

I would imagine anyone with a basic rudimentary mechanical understanding wouldn't attempt to engage the ADD whilst moving and with 4WD engaged. No matter how cleverly you engineer something there is always someone stupid enough to stuff it up.

Maybe we should ask anyone who has installed the switch if they have damaged their vehicle trying to do this, or if in fact they would be dumb enough to engage the ADD in that way...
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Re: Electrically disconnecting the front diff - SR5 only

Postby martynvella on Wed, 09 Mar 2016 7:24 +0000

Batman wrote:
martynvella wrote:Here is another what if question, and the only reason I have not done this mod without incorporating a speed protection circuit.

IF the switch is in L2 and the vehicle is under load , say the boat ramp scenario, rear wheel starts spinning and driver hits the switch with the driveline at speed and under load, would the ADD try to engage and damage the spline?

Or does the ADD ecu already have a speed sensor forcing you to bring the driveline to a rest before it engages.


Martyn I am not being critical of your question, or you for asking it, so please take my answer with a grain of salt...

I would imagine anyone with a basic rudimentary mechanical understanding wouldn't attempt to engage the ADD whilst moving and with 4WD engaged. No matter how cleverly you engineer something there is always someone stupid enough to stuff it up.

Maybe we should ask anyone who has installed the switch if they have damaged their vehicle trying to do this, or if in fact they would be dumb enough to engage the ADD in that way...


I see where you are coming from, but there is always a scenario, lending your car to someone is always a big one.
If there isn't a speed protection already built in to the system then one should be added when the mod is done.
If someone puts up a mod in a forum and someone uses it(and the poster has no control how stupid they are) and it damages the car due to moding the original design and allowing some complete twit does something in ignorance, the original poster can be held responsible by law. That is why professional indemnity insurance exists.
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Re: Electrically disconnecting the front diff - SR5 only

Postby nicebike on Wed, 09 Mar 2016 8:09 +0000

If rear wheels are spinning significantly faster than road speed, big crunching noises are going to be the result if you simply pull it into 4wd from 2wd, never mind engaging ADD.

Basic 4wd technique to go from 2 to 4 is always to momentarily get off the loud pedal, flick the lever and then back on the gas. On the boat ramp, you would stop, engage 4, or turn on add, and try again.

So the potential for stupid to kick in is present, with or without the switch.
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Re: Electrically disconnecting the front diff - SR5 only

Postby martynvella on Wed, 09 Mar 2016 1:24 +0000

FFS
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Re: Electrically disconnecting the front diff - SR5 only

Postby xychix on Wed, 09 Mar 2016 2:19 +0000

I also doubt if there is such a sensor in the car for engaging rear diff lock. Which (if done under full load) will also result in broken halfshafts.

Valid question though! it's always wise to think things trough :)

I'll dive in the EWD to see if I can find a speed limitation for engaging Diff Lock, however the switch is, as batman says just an extra switch is a line that is already switched.
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Re: Electrically disconnecting the front diff - SR5 only

Postby nicebike on Wed, 09 Mar 2016 2:49 +0000

martynvella wrote:FFS


Can't argue with that :lol:
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Re: Electrically disconnecting the front diff

Postby xychix on Mon, 14 Mar 2016 2:53 +0000

Batman wrote:
There is no need to engage in 2WD,as you can see one axle is attached to the diff centre at all times, even in an open diff this connection will be enough to rotate the diff centre and lubricate everything.


If the lubrication is plentiful why does the manual require monthly 4x4 driving in order to lube stuff?
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Re: Electrically disconnecting the front diff - SR5 only

Postby xychix on Mon, 14 Mar 2016 2:56 +0000

I've applied the mod on my new car.

A swich with a led build in.
in open it will light up (consuming some miliamps from the 4WD ECU to ground) when 4WD transfercase position is chosen (read gearbox switch is closed).
in open and 2WD there's no current trough the led and high resistor as there is a direct route to ground

In closed the led is never on al all works as before.

The most nerve wrecking was actual cutting of the wire :P the rest was a piece of cake.
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Re: Electrically disconnecting the front diff - SR5 only

Postby xychix on Sat, 19 Mar 2016 12:30 +0000

I found a swiitch here:

http://nl.aliexpress.com/item/12V-Bar-R ... 9.7.26RHXh

cheap!

They are nice, and you can sandpaper them, sticker a new logo on it, paint the rest, remove the sticker and have a custom button !!! (so far this part faild is is ugly, just scratched 2WD LOW in paint)

how the switch works by default:

1st half of the switch (R-Y and B) is not switched and only used to permanently power 1 LED.
2nd half of the switch (R-Y and G-Y) is switched, circuit closed if the switch is in IN position.

I wanted stuff to work different so I resoldered the internals in order to work as switch for 2WD LOW

I made it work like this:

R-Y (on the R-Y and B part) is used to power both LED's and only if the button is pressed. (took cutting 2 board lines with a dremel and soldering 3 tiny wires. It takes 12V IN (on ignition so you want)

B goes to the blackwire that goes to the black wire that continues TROUGH the gearbox switch to ground. This means the LED only come ON if the button is in pushed position (so it takes 12V to the leds) and the gearbox is in 4H or 4L (so the ground is a real ground)

G-Y is connected to the 4WD ecu, getting 12V signal that has to be put to ground if you DO want to activate ADD. meaning if the switch is in OFF position this needs to be wired to the black trough the switch (another 2 cuts and a tiny wire) of the button is pushed the G-Y wire is connected to the R-Y next to is. This line stays disconnected.

Make sure you measure properly. all the 3 left legs of the internal switch are connected to the 3 on the right. I used a dremel to wipe the copper traces between them.


Image
the result:
Image
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Re: Electrically disconnecting the front diff - SR5 only

Postby aandy on Sat, 19 Mar 2016 5:37 +0000

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Last edited by aandy on Sun, 01 Oct 2017 11:26 +0000, edited 1 time in total.
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Re: Electrically disconnecting the front diff - SR5 only

Postby martynvella on Sat, 19 Mar 2016 9:16 +0000

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Re: Electrically disconnecting the front diff - SR5 only

Postby xychix on Sat, 19 Mar 2016 2:19 +0000

martynvella wrote:http://www.aironboard.com.au/store/products/switches/toyota-switches/toyota-push-switch-laser-etched-878b-2wd-low-range-dual-led-blue-on-off.html


Thanks :) but they only deliver in Australia, Holland EU is quite a bit further.

viewtopic.php?f=13&t=1290&start=220#p389666

as I requested a Mail Relay here but didn't find any yet I'll have to create something myself :D :D


-- edit --

I've designed a custom logo and found a 'laser edge' shop that can burn in the top layer (black paint) for 15Euro's

Meaning I'll have my button at roughly 19 euro total cost :) custom logo.

my design:
Image

With the wiring I have prepared now the button will light up blue (might change to red later) ONLY when button is pressed AND 4WD small lever is in 4H or 4L (in other cases the leds won't find a ground)

As the car is brand new (~8 weeks now) I like to do things exactly as i want them :D :D :D
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Re: Electrically disconnecting the front diff - SR5 only

Postby xychix on Wed, 23 Mar 2016 3:31 +0000

Yess turned out GREAT!

Image

I'd do the same for next projects for sure!!!
I had already damaged the button a bit myself. The etching works like a charm!
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Re: Electrically disconnecting the front diff - SR5 only

Postby xychix on Sat, 02 Apr 2016 3:17 +0000

aandy wrote:Looks factory :?

yeah... that scratching didn't really work... pretty happy with the final result from the laser etching guys
especially as the image and text is self drawn on my computer :)
(sorry for the 90degrees turn)
Image
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Re: Electrically disconnecting the front diff - SR5 only

Postby xychix on Sat, 02 Apr 2016 3:39 +0000

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Re: Electrically disconnecting the front diff

Postby taresk on Sun, 14 Aug 2016 7:05 +0000

xychix wrote:
If the lubrication is plentiful why does the manual require monthly 4x4 driving in order to lube stuff?


This is because when filled to the brim, half of the gear set is still up out of the oil (diff can only be filled as high as the filler hole), which means it needs to rotate occasionally to keep everything coated.
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Re: Electrically disconnecting the front diff - SR5 only

Postby Jason Baldock on Sat, 22 Oct 2016 1:30 +0000

Has any one done this to an sr I have a 2010 wiring looks a little different than batman pics
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Re: Electrically disconnecting the front diff - SR5 only

Postby adampwhit on Sun, 23 Oct 2016 4:55 +0000

You can't Jason. The 2010 SR doesn't have ADD. I don't know when they put it in SRs but my 2013 model has it. If you want to check just make sure you are in 2wd and climb under and spin the front driveshaft. If it won't spin you don't have ADD. If it spins you do. (Or something is broken :) )
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Re: Electrically disconnecting the front diff - SR5 only

Postby Skotyp on Mon, 21 Nov 2016 4:31 +0000

I have got a sr5 front diff and want to install it in a Sr. It has add. Has anyone done this yet? Or have a wiring diagram so that this can be installed via a switch and power or tell me what pins on the add do what?
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