Since its been snowing alot lately ive been leaving my push button 4wd engaged when i park it at night. Is this a good practice or since its getting bitterly cold at night should i dis engauge it for the risk of it freezin into the position its already in.

i would think the chances of it "sticking" are very slim.

 

the biggest danger is probably not being in the habit of leaving it in 4WD. the more often i've gotten lazy like that, the easier it is to forget or have it in 4WD when you don't want.

Also is there some sort of powers switch. Is it like 60/40 power ratio for the 4wd. When i try to do a dounut it seems to pull more from the front then push from the back so i was wondering if there was a sort of power ratio.

that's typical behavior

there is no torque divider for front-rear split

You might get a better answer if you told

us what model Subaru and transmission you are driving.

 

The 4wd engages differently in the 3AT vs the manual tranny.

 

Since this is old gen forum

both tranny types lock the front and rear drives

together just like a Jeep or 4wd truck when shifted

into 4wd.

 

No split no "power ratio"- straight lock

yeah what you're describing doesn't sound like trans related issues. probably tire or traction. the front has all the weight, that accounts for tons of traction related things.

Your just getting understeer from the front tires spining

I can do a dounut fine, but its more of a 4WD drift/dounut. Which is fun!

 

I thought I read in the owners book that in the On-demand 3AT EA82 dis-engauges when the vehicle is turned off. so nexted time you start the car its in 2WD. but I never it. I always dis-engauge the 4WD everytime I park anywhere. its only a push of a botton lol.

 

btw Dude, did you get alot of snow in IA like we did in lower east WI? Waukesha were I live got about 1ft.

The PB 5-speed system is vacuum, like the FT trannies with a locking center diff so once the vacuum has leaked out of the system after the vehicle is shut off, then it'll disengage. It'll engage once you start the car if you leave the button pressed. I think the same goes for the 3AT as well but I'm not 100% positive.

The PB 5-speed system is vacuum, like the FT trannies with a locking center diff so once the vacuum has leaked out of the system after the vehicle is shut off, then it'll disengage. It'll engage once you start the car if you leave the button pressed. I think the same goes for the 3AT as well but I'm not 100% positive.

 

 

 

Oh, I get it! yeaI think the 3AT is the same, cause I had to replace the Vaccum modulater a few months back (Sucking trannie fluid into the air intake) making for a smoke show!

 

Now one question, what moves in the trannie to lock in 4WD? is it a gear that slids, or is it like a rear diff locker?

Oh, I get it! yeaI think the 3AT is the same, cause I had to replace the Vaccum modulater a few months back (Sucking trannie fluid into the air intake) making for a smoke show!

 

Now one question, what moves in the trannie to lock in 4WD? is it a gear that slids, or is it like a rear diff locker?

 

I'm not sure about the 3AT (but I can check here in a sec) but the 5-speed has a gear with a synchro that slides back and forth to go from 2hi, 4hi and 4lo, just like shifting gears in a regular tranny. The vacuum modulator pulls on a shift fork like a shifter moves a shift fork inside the tranny to change gears.

 

Looks like the 3AT uses the tranny fluid to pressurize a clutch pack to lock it into 4wd. Its hard to explain but if you know how an automatic tranny work, it takes the transfer clutch pack and locks it together when the line pressure is diverted to it.

so once the vacuum has leaked out of the system after the vehicle is shut off, then it'll disengage.

really? guess i never thought about it, but loss of vacuum will make it disengage, that's surprising.

 

the ones that need "coaxing" out of 4WD might not let out just due to vacuum leakage maybe? some of my XT6's have needed help getting unlocked. like some driving straight time at slow speeds, etc.

really? guess i never thought about it, but loss of vacuum will make it disengage, that's surprising.

 

the ones that need "coaxing" out of 4WD might not let out just due to vacuum leakage maybe? some of my XT6's have needed help getting unlocked. like some driving straight time at slow speeds, etc.

 

Well if the mechanism isn't disengaged like you're talking about where you have to drive straight for it to, the vacuum modulator isn't putting pressure on the shifter so it'll "pop" out when you drive straight. So even thought the shifter is still engaged if you park, the vacuum isn't putting pressure on it so your luck of it freezing or doing something else like that is almost none. The only time it'll freeze if its not used and corrosion gets into the cable that pulls the shifter fork for the 4wd engagment.

the center diff lock doesn't need constant pressure to say locked (or, mine doesn't at least....might not be normal operation). when I first put my RX trans in, I didn't have the rear end done, or the vacuum solenoids hooked up. I crawled under there, and shoved the lever in to the lock position, and ran FWD like that for months, without any vacuum lines hooked up.

the vacuum diaphragm in the 4wd manual transmission car

is pulled two ways

 

When the button is pushed

solenoid A opens and the diaphragm is pulled to engage

4wd. It in turn (via cable) operates a lever shifting

the rear drive into gear.

 

It will stay in 4wd even if the vacuum bleeds off.

 

To get it out of 4wd, when the button is moved to the 2wd

position, solenoid B opens and vacuum is introduced to the other

side of the diaphragm and it then pulls the lever

taking it out of 4wd.

Thus if ice slush and other debris gets into the area of the

4wd shifting lever it could "freeze" into one

position or the other

 

 

The 3AT automatic 4wd works just as Caboo says.

There is no diaphragm used, it's a solenoid operated hydraulic spool valve.

Which being inside the tranny is not affected by snow ice ect.

 

Thus my original comment on which tranny the dude has.

go skip, that's niftt, thanks for sharing!

 

I crawled under there, and shoved the lever in to the lock position, and ran FWD like that for months, without any vacuum lines hooked up.

i've done that with XT6's before as well.

Ah yes, no wonder why it wasn't adding up in my head. Guess thats what I get for thinking while being sick:-\

I'm not sure about the 3AT (but I can check here in a sec) but the 5-speed has a gear with a synchro that slides back and forth to go from 2hi, 4hi and 4lo, just like shifting gears in a regular tranny. The vacuum modulator pulls on a shift fork like a shifter moves a shift fork inside the tranny to change gears.

 

Looks like the 3AT uses the tranny fluid to pressurize a clutch pack to lock it into 4wd. Its hard to explain but if you know how an automatic tranny work, it takes the transfer clutch pack and locks it together when the line pressure is diverted to it.

 

I know sum as to how an auto trannie works, enough to understand what you explained (So thats a start huh!) Thanks for helping me understand my trannie a little more, and giving me some info to how the 5spd locks into 4hi and 4lo.