Centre Diff lock on AWD auto.

Fatz · Post by **Fatz** » Fri Dec 02, 2005 8:52 am

Hey all, i have a auto AWD, and i want to make it have selectable centre diff lock, yet i have no idea how to do so.
Has anyone done one of these before?
A mate told me that you have to do something like this...

You need to supply 12v to the Duty C solenoid in the centre diff and it will lock like a selectable box.

Is there anything else involved?

Cheers guys.
Fatz
P.S, hoping to have it done b4 christmas

Ben · Post by **Ben** » Fri Dec 02, 2005 12:32 pm

12v to duty solenoid C will unlock the centre, opening the circuit will lock the solenoid and so give a 50/50 split

It is as easy as that!

Use a DPDT to switch to a dummy load so the ecu thinks its doing something and doesn't throw error codes though.

Fatz · Post by **Fatz** » Fri Dec 02, 2005 5:52 pm

ohh sweet, now for my next question, where do i find this solenoid, and what are the wireing colours? n stuff.
Cheers
Adam

Fatz · Post by **Fatz** » Sun Dec 04, 2005 10:03 am

anyone??

vincentvega · Post by **vincentvega** » Tue Dec 06, 2005 9:11 am

Do you a deal. you tell me all about fitting outback struts in the front of an L, and i will dig up a wiring diagram for you

Fatz · Post by **Fatz** » Tue Dec 06, 2005 10:08 am

ahh you are a tricky one arnt you

i bought the car as is, so im not too familiar with the process. here is a pic of the engine bay, obviously there is some modification of the strut tower to fit the larger struts in there.
i bought the car off legacytt, so you can direct any specific questions to him, or to me and ill pass on if you wish.

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Cheers.
hope that is enuf info for the wiring diagram.

Adam[/img]

To fit the OB struts I used Lib strut tops and springs and a bit of FBH. But if you use WRX/Imprezza springs/top hats they will fit with no bashing

Also mine engine/gb is series 3 gen 2, if you have that diagram??
Ta`

Ben · Post by **Ben** » Tue Dec 06, 2005 5:17 pm

L series strut tops fit on Liberty struts (with liberty spring tops)

You got any pictures of the hub end of the strut (or is there liberty brakes too?)

Fatz · Post by **Fatz** » Tue Dec 06, 2005 5:41 pm

yeah lib brakes too

vincentvega · Post by **vincentvega** » Wed Dec 07, 2005 9:28 am

now that i know which car your talking about -

your going to have to get some more info out of ian. I think you may have a VTD gearbox out of a twin turbo gen2, in which case the info about the dutyc solenoid is wrong. If you do have this box still there is no need to lock the diff up anyways - they drive the rear very strong as is

Fatz · Post by **Fatz** » Wed Dec 07, 2005 9:35 am

yes it is the TT gearbox,
but i find that going up hills, once 1 wheel is off the ground(front or rear), that is the end of it, thats the only wheel thats spins and im stuck.
Is there a possibility that the lsd could be worn?
Thanx

vincentvega · Post by **vincentvega** » Thu Dec 08, 2005 8:00 am

if your still spinning a rear wheel then your problem isnt the centre coupling, its the rear diff...

i think you have a viscous LSD from memory, they arent a locker. you will still get a fair amount of slippage until they heat up enough to bite

but if it really is as you say spinning only one wheel, then something strange is going on with your center coupling. are you absolutely sure your only spinning one wheel?

Fatz · Post by **Fatz** » Thu Dec 08, 2005 8:12 am

Thanx,
Is there anything that i can do to make it perform better off road?
No not really, all i know is that i drive up a steep rutty hill, my mates with manual d/r make it up there ok, but when its my turn, as soon as i go into a rut, and a wheel is off, my car just sits there, revving, not sure which wheel it is, or if it is two wheels, maybe the firm suspension has something to do with it? but all i now, is that it is REALLY easy to become stuck up a hill.. Maybe im expecting too much from the auto? i dont know?
Cheers

MY_STI · Post by **MY_STI** » Thu Dec 08, 2005 9:35 am

from what ive seen the centre coupling is ok, but it seems like the rear LSD is having a cup of tea and watching, on loose gravel the grounded rear wheel doesn't appear to even try to drive, but how should a viscous LSD behave?

Hope it gets sorted, i need some competition

vincentvega · Post by **vincentvega** » Thu Dec 08, 2005 10:50 am

sounds like you have a couple of problems.

outback struts are going to be fairly stiff for the weight of your car, so your wheel travel is probably limited and your probably flying wheels more than the other guys.

sounds likethe other problem is your rear LSD is not in the best condition. You could swap in a clutch type LSD which will work alot better offroad, especially if you have it rebuilt nice and tight. most of the guys running RX turbos offroad have a tightened clutch LSD rear and they work really well.

Fatz · Post by **Fatz** » Sun Dec 11, 2005 10:41 am

thanx very much for your help mate

Fatz · Post by **Fatz** » Tue Dec 13, 2005 8:58 am

Does anyone have a clue or pretty close guess to where abouts this solenoid is, or at least what is looks like??
Also MY_STI was telling me, that there my be a thicker old, or some sorta oil that will make the LSD perform better, any u guys now where i can get some, or what it is called?
Cheers all.
Fatz

legacytt · Post by **legacytt** » Tue Dec 13, 2005 9:58 am

If you have a wheel in the air at the back the LSD won't work regardless. May be worth disconnecting the rear sway bar for offroad use and possibley even the front. Sounds like it is struggling to keep the wheels on the ground. Either that or go a bit faster, not as if you are going to hit anything!!!LOL.

Fatz · Post by **Fatz** » Tue Dec 13, 2005 10:12 am

Lol true.
Thanx for that.
Are there any dangers takin off the sway bars for offroad usage? maybe even a little onroad?
Cheers

legacytt · Post by **legacytt** » Tue Dec 13, 2005 8:07 pm

No dramas without them, just a little more roll on the corners. I had just the rear for a while till I fitted the links for the longer front arms. If offroad is a focus it may be worth trying without them completely for a while and see how you like it. I also have some softer front springs you can have if you want to come and get them. . It has turbo springs in it at the moment which are stiffer.

Fatz · Post by **Fatz** » Fri Dec 16, 2005 7:54 am

Ok i posted on ultimate subaru and i got some more information

"subaru really should have made this option available from the factory. i have done it, it's not that hard. need someone with an FSM to tell you which wire to splice into in the engine bay. i'm out of state so i can't look at mine right now, but there's only one wire you need to splice into i believe. run it to a toggle switch in the cabin and use a two pole switch so that you can also wire a light in line with it. i installed a light that comes on when it's engaged that way i know if i accidentally turned it on (or someone else) or forgot to turn it off.

being that there isn't a true center differential in the automatics, the Duty Solenoid C controls the rear transfer clutches.

THE AUTOMATIC TRANS ROCKS WITH THIS MODIFICATION!!!!!!! anyone driving an automatic does not know what kind of snow, mud, off road kind of machine they are in until they install this ONE switch on one wire. it's unbelievable the difference it makes, the tires will never slip this way. i hated the old days of relying on the TCU to control lock up....it didn't lock up nearly enough for how much i drive offroad, in mud and snow.

all you need to do is find the wire in the trans harness in the engine bay for Duty solenoid C. that's it. cut it, splice and run wire to the cabin to install your switch and pull 12 volts from somewhere (radio or fuse box or cigarette lighter). it's super easy, i'm an electrical idiot and did it. someone with an FSM can look up the wiring diagram and post "Terminal 34" "Red wire with Green Stripe"...whatever it is, and that's all the info you need.

i can't say enough how great this makes the auto trans. DO IT! i have an impreza OBS that i'd like to do this too as well, so if someone figures out which wire it is on the newer generation 4EAT trans, post it here.

i've done it on an older XT6, the earlier 4EAT trans so it'll be different than what these newer trans are.

good luck, hope someone posts this info....and post how happy you are after you do it. it's awesome."

so does any one know where i get get a fsm is?????
Cheers all.
Fatz

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