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How Does Subaru 4X4 Work?


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Okay so I have heard lots of different things about older subaru 4X4s. Most recently, a "friend" (I put friend in quotes because I dont actually like the guy at all, he can be a real dumb @**) of mine claimed that my particular 4x4 system on my 84 GL wagon spins the EASIEST rear WHEEL when traction is low. this goes against all that I have thought of four wheel drive because, in my mind, I your tires are spinning, the 4x4 system should either A... send as much toque to the wheel that has lost traction. or B... send equal torque to all tires to help out the one tire that is slipping. Also, then it would be considered a 3x4 not a 4x4 system. So guys, who is in the wrong here, and just how do these subaru four wheel drives work? I also ask this because I know that pretty much all companies have different types and versions of 4x4, and was wondering how subaru makes theirs.  Thanks all!

Edited by Sapper 157
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Your "Friend" is correct.

 

ANY4x4 vehichle without some type of locking differential will lose traction and spin the easiest wheel. Doesn't matter the make.....Jeep, Hummer, Subaru, Chevy, Dodge, Toyata.......all of em.....If it doesn't have a locker......it's gonna do that.

 

Read about differentials.

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Is it possible to put a locker on a soobie?? 

 

Not really.  Nobody makes one.

 

You could fab in some other type of diff that locker is offered for....but that's a huge fabrication project.

 

If your gonna wheel it alot just weld the rear diff.  That's the common practice here.  If you do , It's a good idea to pull 1 rear axle out for street driving in dry weather.

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Ok thanks. I was hoping that there was a way to put a locker on it without welding but oh well I guess. Bandit (my soob) can get out of just about anything with his 4WD engaged as it is right now... Just wished I could have made it even better ya know? thanks for your insight gloyale!

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Another option is to convert the rear brakes to disks that have an e-brake (theres a couple write ups here about that) and then add a 2nd parking brake handle, and separate the cables. So you'd have one handle per rear wheel, and could manually lock up one side or the other, on the fly.

Edited by spazomatic
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Another option is to convert the rear brakes to disks that have an e-brake (theres a couple write ups here about that) and then add a 2nd parking brake handle, and separate the cables. So you'd have one handle per rear wheel, and could manually lock up one side or the other, on the fly.

Niiice...

Never would have thought of that!

I love this forum.

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On the older models - Loyale and back - the front drive and the rear drive do not have a center diff, so power goes to at least 2 wheels - 1 front & 1 rear, even if you are on ice.  Somewhere [manual or shop manual] I read that some models had limited slip diffs.

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recently ive heard about people putting Lsd diffs into the transmission in the front so they can have the front and rear differentials limited slip

 

sounds like some awesome off-roading/rallying to me :D

Almost positive that requires a transfer case though

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The OBX diff made for 94- Imprezas will fit an RX dual range, not sure what other models. It will fit the 5MT fwd transmission with custom bearings also.

 

Edit: Both the helical front and clutch rear would have to be setup with max preload to prevent a wheel in the air from spinning.

Edited by Ibreakstuff
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Theres a third option for thous who are willing to wait. This locker will replace your existing spider gears in your R160 differential. Lets hope i get one in application sooner than later...

 

:D :D :D :D :D :D :D :D :D :D :D :D  My pride and joy haha only about 200 hours of designing. and this is a working model

11816_3677969626860_225859285_n.jpg?oh=7

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Theres a third option for thous who are willing to wait. This locker will replace your existing spider gears in your R160 differential. Lets hope i get one in application sooner than later...

 

:D :D :D :D :D :D :D :D :D :D :D :D  My pride and joy haha only about 200 hours of designing. and this is a working model

11816_3677969626860_225859285_n.jpg?oh=7

 

Yep I'm waiting !  :P

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The OBX diff made for 94- Imprezas will fit an RX dual range, not sure what other models. It will fit the 5MT fwd transmission with custom bearings also.

 

Edit: Both the helical front and clutch rear would have to be setup with max preload to prevent a wheel in the air from spinning.

does the RX tranny have different bearings than the 5mt optional front wheel tranny

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does the RX tranny have different bearings than the 5mt optional front wheel tranny

 

No idea, but I am sure someone else will chime in.

 

My experience is limited to tinkering with the RX DR (87-89), FWD (only) 5MT EA (87/90), and several flavors of FWD/AWD 5MT Impreza (93-95) gearboxes . The RX DR and Impreza AWD 5MT's (late94-95 FWD also but hard to find) have the same front diff (will fit the OBX LSD). And as far as I could tell the EA FWD (only) 5MT has the same front diff has the 93-early94 FWD Impreza gearbox.

Edited by Ibreakstuff
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  • 3 years later...

What about the full time 4wd EA82 cars? These must have had center differentials, as some of them have the “diff lock” button.

 

Is the Full Time 4wd in these cars (GL10 Turbo wagons are the ones I see most frequently) inanyway similar to the AWD on my Forester XT?

Similar. They both have center diffs. The AWD trans has an additional viscous coupler that acts like a limited slip device. The FT4WD is simply an open diff (some were lockable).

 

Or in the case of the Automatic model it's exactly the same transmission only the name changed.

 

GD

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What about the full time 4wd EA82 cars? These must have had center differentials, as some of them have the “diff lock” button.

 

Is the Full Time 4wd in these cars (GL10 Turbo wagons are the ones I see most frequently) inanyway similar to the AWD on my Forester XT?

 

The 86 - 89 EA82T RX2 (Leone /Omega - Rally)  coupe had a full time AWD dual range 5MT (20% reduction) with a centre locking diff (electric actuator / button) and rear LSD

And the SVX coupe  in 1991 with VTD and VDC?

 

Superior to any other Subaru AWDs  until VDC was introduced in 1998 into some 2nd Gen Outbacks / 3rd gen Legacys  (BE / /BH platforms)

apart from some H6 2nd gen Outbacks that got rear LSDs  along with  earlier Legacy GTs, 

 

 Not sure about Forester XTs or GL10 Wagons  in US.

Would imagine the Foresters would be the standard full time AWD setup of a centre diff with a viscous coupling in manual versions and the multiplate transfer clutch in Auto versions.   

 The GL10's if full time AWD would have been similar

Don't know for sure but maybe Forester XT got a rear LSD.

Edited by subnz
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