Boy did I have a scare today! Still a little concerned...
- Thread starter SubieRubyRoo
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Negative, you’ve got it backwards. The Subaru manuals (non-STI w/DCCD) are always split 50/50, mechanically. They are non-LSD on all models as far as my research shows. Not sure if Legacy/Outback have LSD on manual.
Subaru 4EATs are initially close to 50/50 upon initial acceleration or low-speed wheel slippage. As vehicle speed increases, the rear wheel viscous center diff and clutch pack releases significantly, making the split somewhere around 90/10. Yes, at highway speeds, auto Subarus are essentially FWD. If the system determines wheel slippage, it quickly engages the central viscous unit to re-distribute torque. The only 4EAT/LSD combo was on the Legacy/Outback. Foresters and NA Imprezas are all peg-leg rears.
STI’s w/DCCD are a hybrid adjustable. They can be set for a fixed 35/65 to an equal 50/50 thru a center console dial. AFAIK all STIs are LSD rear.
Mine was older, 1997. It was a manual with center diff, and that diff had a pretty stiff limited slip. It was highly desirable compared to the automatic fwd with rear wheel engagement via limited slip clutch, electro-magnetically biased. The auto system gave some folks trouble when turning as it wouldn’t “let go” enough (chatter). As an aggressive snow pirate, the LSD center diff setup in the manual was a the bomb. Effective, nothing to go wrong, stout. It was not open.
some of the manuals had an electrically biased center diff which used offset gearing to influence more torque one way or another.... in Maybe the wrx’s,(?) - I’m not as familiar with those.
Forester XT's and the higher L.L.Bean trims are not peg leg rears regardless of manual or auto. I know for a fact my 05 Forester XT had a viscous rear LSD and the viscous center diff.
I had a much older EJ22 powered Scooby ('95) Legacy wagon. It was front wheel biased @ about 90%, to rear 10% on flat, dry, highway speed pavement. So yeah, it understeered like a lazy torpedo as many unmodded FWD cars will.
She had a classic thermo-viscous center differential that could bind up evenly, 50-50 front to rear, but at least one front tire has to slip for about 2 seconds before she would lock up and just dig in on the rear axle.
But when she hooked up? Bro (and sisses)... unbeatable in the early days of Selec-Track, GM AWD, and auto 4x4....whatchyamagottit.
But yes, very true of the older generation models until they came up with electro-magnetic torque distribution...a hard turn over on the wheel to get into a parking spot can make the wagon rapidly bind-unbind-hitch-a-hump into a parking stall.
Licensed Subaru tech friend @ time said it was expected, low speed behavior on dry, hard surface. Not a particular issue. It was when you had the hitch-a-bump with tire squeals and scrubbing under same low- speed, hard turn maneuvers (i.e. parking) that it warranted repair.
With time, extreme milage and-or lax center differential maintenence that the clutch pack/plates can bind together and not release properly from fluid contamination or worse, plate and clutch fragmentation. The only fix was a rip and replace.
She had a classic thermo-viscous center differential that could bind up evenly, 50-50 front to rear, but at least one front tire has to slip for about 2 seconds before she would lock up and just dig in on the rear axle.
But when she hooked up? Bro (and sisses)... unbeatable in the early days of Selec-Track, GM AWD, and auto 4x4....whatchyamagottit.
But yes, very true of the older generation models until they came up with electro-magnetic torque distribution...a hard turn over on the wheel to get into a parking spot can make the wagon rapidly bind-unbind-hitch-a-hump into a parking stall.
Licensed Subaru tech friend @ time said it was expected, low speed behavior on dry, hard surface. Not a particular issue. It was when you had the hitch-a-bump with tire squeals and scrubbing under same low- speed, hard turn maneuvers (i.e. parking) that it warranted repair.
With time, extreme milage and-or lax center differential maintenence that the clutch pack/plates can bind together and not release properly from fluid contamination or worse, plate and clutch fragmentation. The only fix was a rip and replace.
So I’ve heard two different stories on the above system for all of the automatics, but never had an automatic to figure it out for myself. of both stories, this was common: it was a FWD with a set PTO to the rear, through a magnetically modulated limited slip clutch, to the rear. The first way it was described to me, was more of a traditional AWD where the typical operation was just the limited slip clutch with the tail rolling behind, until power was applied and it would begin to lock up. The other is more interesting : that it was typically largely engaged and power was applied to separate the clutch plates and loosen it up during a turn or perhaps higher speed cruise. The fella who told me that also explained that’s why installing the 5A fuse on the firewall turned it into just FWD, as it applied 100% power to unlock the clutch.
im inclined to believe the latter more, because back in the 90s, even the automatic subarus were known for quite outdoing the AWD Volvos with the more traditional systems in heavy snow or thick mud. they were aggressive and effective in the snow and, within reason, off road.
AFAIK, this system was the only system offered in the automatics as long as the ATs were 4 speeds. It seems they may have changed technologies in the mid 2000s but I didn’t own any past 1997 and lost hands-on with them.
im inclined to believe the latter more, because back in the 90s, even the automatic subarus were known for quite outdoing the AWD Volvos with the more traditional systems in heavy snow or thick mud. they were aggressive and effective in the snow and, within reason, off road.
AFAIK, this system was the only system offered in the automatics as long as the ATs were 4 speeds. It seems they may have changed technologies in the mid 2000s but I didn’t own any past 1997 and lost hands-on with them.
My '95 Legacy EJ22 powered auto 4-sp I think is as you describe. I had a shop strip the drain and fill bolts on the rear diff. It was leaking milky-water treacle by the time they rounded the plugs for me.
I stuffed a fuse in the socket under the hood to "lock" out into FWD only and crawled to Subaru dealership just 5mi down the road.
All said and done, $125 for rear diff service which included an $85 rear diff cover replacement, flush and refill. The bolts were so frozen that I was told 3 service techs on the business end of a breaker bar and cheater pipe almost pitched my wagon off the lift. Replacement and service was the only way. No complaints, they did it right and were so very cool to go the extra mile at near cost.
Once it was fixed, they yanked the under hood fuse and sent it. Never a trouble until I traded her 95k miles later.
Like you I heard that they were a classic thermo-viscous center clutch until later models incorporated magnetic, real- time torque distribution. Placing the fuse in the panel under the windshield cowl on the 95 and earlier models; electrically de-coupled front rear center differential. Normal operation was 90%10% front to rear ratio with the rear wheels actually mechanically dragging just very slightly. The front heavy bias could almost instantly go 50%-50% within two seconds if the front slipped.
It was plain, bare bones mechanical-thermal torque distribution. The newer ones, especially the STI, I think start with a rear bias of art least 60%:40%, making them a sport handling rear thrust car. They also use a real time computer to adjust front: rear torque ratio on the fly and dynamic braking to completely stop a wheel that's got zero traction.
I stuffed a fuse in the socket under the hood to "lock" out into FWD only and crawled to Subaru dealership just 5mi down the road.
All said and done, $125 for rear diff service which included an $85 rear diff cover replacement, flush and refill. The bolts were so frozen that I was told 3 service techs on the business end of a breaker bar and cheater pipe almost pitched my wagon off the lift. Replacement and service was the only way. No complaints, they did it right and were so very cool to go the extra mile at near cost.
Once it was fixed, they yanked the under hood fuse and sent it. Never a trouble until I traded her 95k miles later.
Like you I heard that they were a classic thermo-viscous center clutch until later models incorporated magnetic, real- time torque distribution. Placing the fuse in the panel under the windshield cowl on the 95 and earlier models; electrically de-coupled front rear center differential. Normal operation was 90%10% front to rear ratio with the rear wheels actually mechanically dragging just very slightly. The front heavy bias could almost instantly go 50%-50% within two seconds if the front slipped.
It was plain, bare bones mechanical-thermal torque distribution. The newer ones, especially the STI, I think start with a rear bias of art least 60%:40%, making them a sport handling rear thrust car. They also use a real time computer to adjust front: rear torque ratio on the fly and dynamic braking to completely stop a wheel that's got zero traction.
Nice explanation. this is also what made the manuals such a gold nugget. The stock 5spd drove a true center diff (50/50) with viscous limited slip medium. If you had the manual, it was a true center-driven vehicle and handled so. In mine, it was a hoot with the crummy 14” steelies and economy tires …. modulating the gas in 3rd at 45 to truly drift it around cloverleafs ... you could have a lot of fun and learn finesse in a rather utilitarian vehicle, and it had a very natural body language in snow. It was a jack russell terrier in the snow.
i upgraded wheels and tires, and it became as sure-footed as a bobcat. There was no more drifting with 205/60/15s. Only once did I get wheelspin from a stop, and that was a massive clutch drop in the rain. That car would have been a hoot with a turbo. For as balanced as it was (mine was a wagon), the little 2.2 had barely ok torque but was not over powered.
Aye, that was my experience too. Despite the heavier wagon body, she was a spirited and long legged machine that could eventually scare you at 120+ mph in the dry and solid.
She was unbeatable in ice and snow. She could dig in and find passing power when all the heavier 4x4 and various AWD's would churn and flail into the curb due to road crown. Not too overpowered, but not gutless either especially in the slip-slop-of-snow days.
Mine rode on 13" steels with plastic covers, but I fed her Z-rated Goodyear all seasons. It was the cheapest, no fuss way to put stiffer sidewalls on her as opposed to getting under her and upgrading lower control arms, bushings and LCA support struts to stiffen up the understeer.
That old '95 alpine white "blister" on 4 wheels cornered like it was on rails after that. Her bad weather performance always guaranteed that I was the only dupe to show up to work on snow days... so take that as you will. ^.^
She was unbeatable in ice and snow. She could dig in and find passing power when all the heavier 4x4 and various AWD's would churn and flail into the curb due to road crown. Not too overpowered, but not gutless either especially in the slip-slop-of-snow days.
Mine rode on 13" steels with plastic covers, but I fed her Z-rated Goodyear all seasons. It was the cheapest, no fuss way to put stiffer sidewalls on her as opposed to getting under her and upgrading lower control arms, bushings and LCA support struts to stiffen up the understeer.
That old '95 alpine white "blister" on 4 wheels cornered like it was on rails after that. Her bad weather performance always guaranteed that I was the only dupe to show up to work on snow days... so take that as you will. ^.^
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So any pics yet?
IK,R? I'm excited to see a loved Subaru.
Hopefully seating the half shafts and just a little TLC got it running right again.
The world wants to see!
2009 Forester XT w/ 4spd auto had the fuse as well so I'd suspect your latter is correct. I also think there were slip disc in the axles to prevent binding but I don't know for sure.
The one and probably not so good for the driveline way I found out you could have a limiting slip rear diff in my first Forester XT.
A 3 wheel burnout, 3 because while the back 2 tried to oversteer as I popped the clutch the passenger front wheel also did a one tire fire. It was an unintentional consequence of trying to pull out into fast moving traffic. It worked and the traffic in the opposing lane thought I was a lunatic. I was later showed the ring gear from another person who informed me of what happens when you do this repeatedly. It was missing a few teeth like it went rounds with Mike Tyson. Still miss that car, 05 Forester XT w/ 5sp. Faster than WRX's off the line and could keep up with STI's after a few minor upgrades.
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