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How to engage 4wd


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So, how do i get 4wd to engage? I see that i can do it, by going around a corner hard and make the inside tire on the front spin. But how about having it more often. The car says "full time four wheel drive" on the back.

 

Also, i am looking for the book that came with the car.

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Sorry to disagree with Caleb

You are only in 4 wd when the TCU thinks one set of wheels is spinning at a different rate.

The rest of the time you are in 2 wd only.

If you want to be able to manually "shift" into 4wd

you need to add a switch that disconnects the signal from the aforementioned Duty Solenoid (DS "C").

This DS controls the rear drive shaft clutch pack hydraulic fluid pressure drain.

If it is disconnected the hyd. fluid does not drain and thus the clutch pack locks the rear drive to the front.

We have discussed this at length on the New Gen board.

If you are interested in pursuing this further, I will get the link for you. Or you are welcome to do a search.

Hope this helps

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Sorry, Donald. it is my understanding that the diff lock switch was only found on the manual transmissions - maybe the ones in Canada are different??

(the tranny is listed in his sig. BTW)

 

and

licking the center diff

 

Why would he want to lick his diff??

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If you really wanted to get inventive, you could put a 3 posistion switch on that solenoid.. Flip the switch one way, and it locks it in 4WD, switch it the other way, and it locks it in 2WD, put it in the middle and you have normal FT4WD operation. I dunno if those have a FWD switch like the Legacies do or not, but if they don't, the 2WD mode would be useful if you ever have to run a different size tire in an emergency.

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H.sucks, that is a very good idea.

The only problem I see that may cause a problem is

the duty solenoid is fed a duty cycle signal

and not a full battery voltage.

I do not know what consequences could result if the solenoid

was operated with this voltage for an extended period of time.

In either position other than normal you will get a TCU trouble indicator upon start up.

The early FT4EAT's I have seen do notall have the 2wd fuse

holder behind the pass, strut tower.

I assume this is what you mean when you say

 

"I dunno if those have a FWD switch like the Legacies do"

 

as I have never heard of an actual factory switch for this.

This fuse puts a battery voltage signal to the TCU which in turn disables the rear drive.

This is for dyno testing or situations like you mention.

Good thinking though.

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Originally posted by Skip

Sorry, Donald. it is my understanding that the diff lock switch was only found on the manual transmissions - maybe the ones in Canada are different??

(the tranny is listed in his sig. BTW)

 

and

 

 

Why would he want to lick his diff??

 

but when a diff is locked, it behaves like a part time unit. my point

 

"This kind of speak is not appropriate for the USMB, except for moderators"

 

knowing what the subaru tastes like will help please all your 5 senses

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lol the center diff lock is not on canadian autos, I had one, and the one full-time 5spd ive seen had a diff lock, so I think the transmissions are all the same as US. IMO theres not much point in locking up the center, all I ever managed to do with the 4eat was spin the fronts maybe a 1/4 rev or less before the rears kicked in. At lower speeds on rocks and gravel I couldn't tell that it was engaging/disengaging. If your going to hardcore 4x4 the 4eat is not the one for you anyways, cause it's got no low range.

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You are probably right, Skip, although couldin't you theoretically built a circuit to pulse that duty solenoid on, say, a 90% duty cycle.. OR better yet, use a 555 Timer and some beefy power transistors to make a sort of a variable center diff.. Wouldnt' want to leave it on too long or you;'d prolyl burn up the transfer clutch though... And by FWD switch, I was referring to the FWD fuse.. Some later ones had a swtich under the hood.. You could wire the switch into that fuse holder, so 2WD mode used the ECU, instead of just cutting power to the transfer clutch solenoid.

 

If you knew what the TCU was looking for, it wouldn't be all that hard to fool it so you didn't get a code with the transfer solenoid disconnected...

 

If you wanted to really get into it, you could hook the shift solenoids up to toggle switches, and the TCCC up to a switch, so you can shift gears manually, and lock and unlock the torque converter (unless those don't use a computer-controlled TC Clutch.. (TCCC = Torque Converter Clutch Control).. Man I am on a roll here, I should post when I'm tired more often :-)

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