Change AWD to 4WD?

[jeryst]

I've owned Subarus since the 70's. In my opinion, the models that had the push button 4WD were far superior to the current full time AWD. With the push button cars, I used to have fun trying to find places where I could get stuck. They were like tanks that blasted through deep snow like it wasnt there. But the current full time AWD models just dont seem as capable to me in deep snow because even going through a couple inches of snow makes them slip and slide around. I would never consider taking the full time AWD cars to places I used to go with the old push button 4WD cars.

 

I remember reading someplace, that you can convert the full time AWD to the old style 4WD by installing a switch someplace, and rerouting or reconnecting some wires.

 

Anyone know anything about that?

[1 Lucky Texan]

what car do you have?

[jeryst]

98 Outback Wagon.

 

My first full time AWD was a 94 Loyale Turbo Wagon, and

I immediately noticed a difference in snow related performance

compared to the push button 4WD cars that I owned previously.

[idosubaru]

98 Outback Wagon.

 

My first full time AWD was a 94 Loyale Turbo Wagon, and

I immediately noticed a difference in snow related performance

compared to the push button 4WD cars that I owned previously.

tires. snow traction is heavily correlated to tires. first bias is often towards blaming car, 4WD, and ABS.

 

What brand tires and tell us the 4 digit date stamp on the side wall of all 4. it'll be in a small box/oval outline and just have 4 numbers 0916 or something like that. first two digits are the week (out of 52) in which is what made in a given year, and the last 2 digits are the year (so 16 would be 2016) of manufacturer. if you're ever buying used tires/cars in snow areas you should be good at doing this.

 

i prefer old gen style too like my daily driver XT6 i just rolled into the office with. you could have multiple vehicles too - just get an old EA82 to bang around for the winters. that's what i've done for many years but now i'm headed towards using my XT6 less in the winter to fend off rust.

 

Yes you can add a switch to "lock" an automatic trans just like the old gen stuff, but if you have an MT there's nothing you can do. it's not electronically controlled so it's impossible.

 

in an AT you can install a switch in line with the Duty C wiring. it's just one wire and you're disconnecting/connecting that wire.

with the switch completing the circuit you'll have stock AWD. with the switch disconnecting the circuit you'll have "locked" 4WD just like your old gen push buttons you're talking about.

 

find the duty C wiring by downloading the FSM which are free online. find the wire from the TCU (it's right above your gas pedal) for the Duty C solenoid. Cut that wire and put a switch in line with it. that's it.

 

Typically you extended the wires so you can install the switch somewhere convenient.

Edited January 12, 2018 by idosubaru

[jeryst]

So how did the old MT cars work with a push button? They were FWD until you

pressed the button and then they switched to 4Wd.

 

All I ever had were MTs until I got that 94.

[matt167]

that's an actuator or lever that locks what would be the center diff on an AWD car pretty sure ( have not been around an EA in years ). That's how it worked on the old 4x4 EA cars.  The AWD Automatics use a solenoid to operate a clutch. Provide constant 12v to the solenoid or cut the power makes it 4x4 or fwd depending... The manuals just use a viscous coupling in the center differential. You could have a machinist make a mechanical disconnect/ sliding mechanism but it would be expensive.

[Numbchux]

98 Outback Wagon.

 

My first full time AWD was a 94 Loyale Turbo Wagon, and

I immediately noticed a difference in snow related performance

compared to the push button 4WD cars that I owned previously.

 

Automatic or Manual transmission? The way the AWD system functions is very different.

[Mike104]

I thought MT were 50/50 on front/rear power distribution?

[Bushwick]

Tires as mentioned make a difference. Also, check that the front and rear sway bar end links are NOT broken. When I 1st got my 95', it wouldn't track straight in the snow due to the dog bone links being snapped. Even on inexpensive tires now with an upgraded rear sway bar (either from a Forester or later Outback, can't remember) the car tracks straight and only time I ever got truly stuck, was on junk tires it came with in 6"+ snow on a grass yard which was up the underside of the car, so more of a height + tires issue vs. AWD issue.

 

We had solid ice on the secondary roads last week in early AM hours, and even on that car was fairly straight despite sliding on braking at 10 mph. Mind you this an auto, but it's still a blast in the snow. Very predictable. I've had it in deeper street snow (last year) that was deep enough it was packing into the bumper openings while filling the lower underside plastic in the engine compartment and it just kept going.

 

Also, FWIRW, this car has pulled everything from RAV4's out of ditches (while I was on a snow covered road) to pulling a RWD F150 out of an icy driveway, to pulling a GEO tracker out of an ice patch, etc.

Edited January 12, 2018 by Bushwick

[jeryst]

Current vehicle is automatic.

 

It's just my personal impression that once they got rid of the button and went to full time AWD, the system is just not as good. I had probably 15 vehicles with the push button 4WD, and this is my fourth full time AWD with AT.

[Bushwick]

If it's not tracking straight going down the road, check the end links. WHY these used plastic here is dumbfounding. 35-40 mph should be nearly perfectly straight in the snow.

 

If it's not getting up and moving easily in the snow, and the tires are solid, you might have something else going on. 

 

If all it's doing is spinning the front tires constantly, check there's no fuse in the FWD fuse holder under the hood (should have a dash light on if it's in though I've seen people go so far as to remove a cluster and blot out an LED warning light with RTV to hide something)

[idosubaru]

Current vehicle is automatic.

 

It's just my personal impression that once they got rid of the button and went to full time AWD, the system is just not as good. I had probably 15 vehicles with the push button 4WD, and this is my fourth full time AWD with AT.

 

i agree. i like selectable 4WD better as well.  since you have an automatic you can install a switch and have selectable 4WD with the push of a button. done deal - you can have exactly what you want. 

 

that being said, if it's dramatically lesser in traction - it's still the tires or a mechanical issue with the 4WD. 

 

what is the date stamp and brand of the tires?  we could all learn something here if we get some data on the table. 

 

So how did the old MT cars work with a push button? 

 

they're externally controlled so you can play with those controls - vacuum, mechanical, electronics.  totally different system.  with EJ vehicles it's an internal limited slip device with no external controls, so you literally have no access to it. 

[jeryst]

I'd like an opinion on this from anyone that had the pleasure of owning one of the old push button MT vehicles. Any of you agree (or disagree) that the 4wd in those vehicles was better or more capable in dealing with offroad or deep snow situations?

[idosubaru]

I'd like an opinion on this from anyone that had the pleasure of owning one of the old push button MT vehicles. Any of you agree (or disagree) that the 4wd in those vehicles was better or more capable in dealing with offroad or deep snow situations?

 

i agree with you and i also run locked rear diffs as well for even better traction. 

 

i like that they don't have that momentary "sliiiiip" from a start when you're sitting in mud, nasty snow, off road and you know it's locked when you're coasting down a steep, slick, snow covered grade. 

 

it also depends what kind of snow and how much ground clearance the vehicle has.  if you're pushing a vehiclein snow and mud they're easy to high center in which case drivetrain is meaningless.

 

still haven't heard anything about tires.  i love 4WD but the indisputable facts are that tires can be far more important than 4WD.

[Numbchux]

Current vehicle is automatic.

 

It's just my personal impression that once they got rid of the button and went to full time AWD, the system is just not as good. I had probably 15 vehicles with the push button 4WD, and this is my fourth full time AWD with AT.

 

The AWD system with the automatic is a FWD transmission with some power sent to the rear as an afterthought. Only once the TCU detects a difference in speed between the front and rear does it send a decent amount of power to the back.

 

By manually selecting 1st gear, it does make that program more agressive, so it's a bit less noticeable.

 

Also, it's pretty easy to add a switch inline to the power wire to the transmission solenoid that controls the AWD and lock it down as tight as it can (well documented, you're looking for the duty C solenoid).

 

 

 

An Outback is a MUCH heavier vehicle than an EA82, so it feels much more cumbersome, much harder to control it's momentum.

 

I have owned many 4WD EA82s (To be fair, either D/R 4WD or FT4WD, never push button, but the 4WD functionality is the same with it locked in), and EJs and living in northern MN, I'm no stranger to snow. It is a completely different animal than the old EA82s. I almost swore off Subarus a couple years ago when I was driving a '99 Outback SUS 4EAT. I went up the driveway to my buddies shop that had not been plowed since the last storm. There's a section right by the shop that's off camber, and I slid off the driveway. I managed to get it pointed the right way, but it took me hours with a shovel, jack, and some dimensional lumber to get it back on the flat ground again. In hindsight, the AWD let me down, but mostly the Primewell tires let me down.

 

 

The AWD system with a manual transmission, however, is very similar to the old 4WD.

 

 

I also frequent the local ORV park up here, which used to be an iron ore pit mine, so it's mostly rock crawling, where gearing and diffs are crucial. I haven't had a conventional 4EAT up there, but every other version. Again, the EJ 5MTs don't have much of a traction disadvantage from the EA82s unless it gets really nasty, and even then typically it's the front and rear diffs that let them down, not the center, and gearing. Our '04 Outback VDC (much more like the MT AWD) does very well, need to get it lifted and skidplated to really push it.

Edited January 12, 2018 by Numbchux

[golucky66]

I have an 09 forester that I decided last storm to see how much it could take.

 

I ended up stopping on about a 30-35 degree incline with 9-10 inch of snow (the bumper was plowing snow a little) and I turned off traction control and just gave it gas. I was spinning but I made it up the incline. I was quite in pressed.

 

Though I did have brand new snow tires (non studded)

 

I've driven my 85 brat is some deep snow and that handles great as well.

 

Personally, I find the most important thing with tracking and traction in snow is tires, and a proper alignment.

[jeryst]

On the current full time AWD, how many wheels are putting power to the ground at the same time?

[1 Lucky Texan]

2 if open rear diff

 

2.5 or less with viscous rear diff

 

 

lol

[jeryst]

Ok, I thought it went like this:

AWD: Power is supplied to the wheel with the most traction.

4WD (unlocked): power is supplied to the front wheel with the most traction, and the rear wheel with the most traction.

4WD (locked): power is supplied to all 4 wheels.

 

Where am I going wrong?

[=CC=]

This will be my first Subaru winter, so I don't have any real world experience with it.  However, I handled 8 winters with my old Audi quattro, and with snow tires, it was unstoppable.  As in, we went out twice in a blizzard (when we truly had no business being on the road), and the old guy just kept on going.  That car had torsen AWD, and I thought it was great....as long as I had the snow tires on.  With regular all seasons, that car was squirrely as hell.

 

I've driven selectable 4wd Suzuki Samurais in the snow, and they were ok, but being so lightweight, they had NO problem sliding around, lol.

 

 

I'm actually looking forward to trying out the Outback AWD.  I'm curious to see how it compares to the torsen.  But not until I get my snow tires on it.

[idosubaru]

Nope. Simply speaking:

 

FWD is 1 wheel drive

 

4WD/AWD is 2 wheel drive.

 

AWD/4WD with locked rear diff = 3 wheel drive

 

AWD4WD with locked front and rear diff = 4WD (front lockers are very rare in Subarus).

 

There are three differential mechanisms involved. Power isn’t sent to wheels but ather to input shafts axles and through these diffs.

 

Only one wheel at a time is driven by the front and rear diff. Google differentials for all the guts and detail. nearly every car made for decades uses a differential, you’ll find it easily.

 

Have you ever seen a typical FWD or RWD car stuck? One wheel spins. And a 4WD/AWD without traction control of some sort will functionally spin two wheels when stuck. Anyone playing in real mud and snow enough has seen this countless times.

 

Easy way to see this yourself - put your FWD fuse in and go floor it on a wet road pointing up hill while turning the steering wheel almost fully left or right. You’ll do a mad FWD burn out - one wheel is getting all the power.

 

The center diff mechanism (clutch pack in an AT) “sends” power to the front diff and rear diff. this center diff is where the “locking” (or not) that you’re talking about happens. Then the front and rear diff will (simply speaking) drive one wheel.

[idosubaru]

This will be my first Subaru winter, so I don't have any real world experience with it. However, I handled 8 winters with my old Audi quattro, and with snow tires, it was unstoppable. As in, we went out twice in a blizzard (when we truly had no business being on the road), and the old guy just kept on going. That car had torsen AWD, and I thought it was great....as long as I had the snow tires on. With regular all seasons, that car was squirrely as hell.

 

I've driven selectable 4wd Suzuki Samurais in the snow, and they were ok, but being so lightweight, they had NO problem sliding around, lol.

 

 

I'm actually looking forward to trying out the Outback AWD. I'm curious to see how it compares to the torsen. But not until I get my snow tires on it.

itll so as good as the tires you give it if you see nasty roads. Tires make the difference. Even brand of snow tires and age make a difference. The snow tires I’ve used, even highly touted blizzacks, (though they do really well) don’t perform at age three like they do the first year. I’m trying micxhellin snows now to see how they age, on my second year with them I think.

[el_freddo]

Where am I going wrong?

 

You're talking about different systems in an "all in one" way:

 

EA81/EA82 dual range 4wd: Dual range between engine and gearbox, not at the back of the gearbox like a "traditional"4wd.  Permanent front wheel drive with the rear wheels engaged via a mechanical lock.  Front and rear axles locked together when in 4wd.

 

EA82 single range "push button" 4wd: Same setup as the dual range 4wd minus the dual range part.  Locking device is basically the same but the operation is different.  Locking operation is done via a vacuum diaphragm that pulls/pushes on the lever to lock/unlock the rear end.

 

EA82t AWD dual and single range: Uses an open centre diff for AWD onroad.  Push a button/flick a switch and the same vacuum diaphragm as the push button 4wd actuates a dog clutch on the centre diff to lock it.  This locks the front and rear axles together like the above two boxes.

 

EJ AWD (dual and single range - we got dual range!): centre diff with a ~5kg rated LSD built into it.  This LSD limits the front or rear axle spinning independently of the other.  Some later models got the DCCD setup which is controlled by a module for best traction possible in a variety of situations, it can be manually over ridden too.  This device is being used by many over here for offroading to effectively lock the front and rear axles together as required when offroading.  We're yet to see when/if the coil in the DCCD burns out.

 

EA/EJ auto AWD/4wd.  Effectively the same gearbox setup.  Permanent 2wd to the front with engagement of the rear through a set of electronically controlled clutch packs.  EA's had a switch to lock in "4wd" where as the EJ's had "AWD" via the TCU monitoring wheel spin/need for power to the rear axle.  This is where the switch mod that's been discussed can come in handy for those that offroad or are in very slippery conditions such as your snow driving.  The clutch packs can wear out over time too which is another issue with this setup.

 

idosubaru's explanation of the 4wd systems and their "drive wheels" is also a good way to explain it.  Differential setup is very important in slippery conditions and each driver might use something different according to their driving style.

 

My EJ22'd L series runs a modified EA82t AWD box with 4.11 ratio diffs.  I have a front LSD and an open diff in the rear.  I'm waiting for a locker if it ever eventuates but I've also found that in 99% of my offroading I don't need the rear end locked as when climbing all the weight is on the rear end providing the best traction - until I lift a wheel. So I drive trying to keep my rear end on the ground when offroading.  The Front LSD has been an awesome addition over an open diff but not as good as a manual locker would be!

 

Cheers

 

Bennie

 

PS:  my snow tyres are now about 7 years old and don't see snow work any more.  They've hardened up well and aren't melting in the summer heat like my first set did back in the day.  They're wearing pretty quickly now compared to a regular road tyre, but I'm not fussed about this as I won't be in the snow over here like I was for two years.  They were on an L series in the snow, now they're on my brumby.  They're Toyo Winter iPike's IIRC and to me were a good tyre in the snow

Edited January 13, 2018 by el_freddo

[scalman]

Well AWD/4WD with traction control as VDC/ xmode is not just 2 wheel drive.its dynamic. Its not that simple. And if its 2wd its those 2 wheels that have traction, not those that in air as older active AWD.

Edited January 13, 2018 by scalman

[1 Lucky Texan]

skip to about 3:00

 

 

 

 

Edited January 13, 2018 by 1 Lucky Texan