How Subaru's AWD System Works 

This is by far the best explanation of this system... Thank you, I truly appreciate it.

Man you are better than most car shows out there Alex! I learned a lot more with you than those flashy television programs. Keep up the good work homie!

This is among the very best, easy to understand, short and to the point explanations about Subaru's AWD system.

I enjoy almost all reviews on youtube, but yours are the most informative and useful to me. Clear and direct without an obvious bias, or if there is you say you have a like for a particular car. And your explanations of the mechanics behind the running of the cars is informative and understandable. Keep up the good work. Thanks

So the difference is audi and subaru always send some power to the rear wheels? We have snow/ice races here in Alaska and the subaru's and audi's always win. The 4matic and Xdrive always shut on and off it's like they are confused on the ice. How do the Lexus RX 350 AWD work? Is it FWD based until slippage occurs? They should use the Audi's AWD or Subaru it's better. I bought a Subaru Outback for my wife it feels like it's on rails in the snow. I want to get her a Lexus RX but if it's not better AWD system then I will buy another Subaru. RAV4 AND CRV should not be allowed to be labeled AWD they get stuck in light dusting of snow. Thank you Alex for taking the time to explain these systems. Let's see the new Outback and Forester reviews!

Awesome video and great information. I'm thinking about getting 2015 Subaru Outback, and have visited 2 dealerships to find out details about the vehicle and the difference between 4wd systems for the CVT and 6-speed manual. At one the salesman said they are the same systems. AT the other the salesman asked 2 other guys, and then went to check with a mechanic to get very limited answer. Your reviews rock. Big props for the detailed info.

Thanks for the video. Took me forever to find a clear, concise explanation of the Suburu AWD. Liked and subbed 😊

Those dashes that you drew at 1:52 - very impressive!

Best and simplest explanation of how Subaru AWD works. Great Educational vid anybody can understand

You are very good at explaining this. Please make more such technical videos. Between yourself and Engineering Explained, you guys have it covered 🙂

Best explanation of this system so far.

Great vid! Probably the most concise and understandable explanation I've seen in a while. One note, related to your last comment... it's more than just how the computer is programmed. One also needs a rear differential and a center transfer mechanism that can handle more power. One car manufacturer in particular, started marketing their limited duty AWD system more aggressively into the off-road segment, and ended up having issues with burnt out rear ends from things as simple as beach travel. If the clutch packs and rear end can't handle the necessary power, bad things happen. ;-)

I finally understand how the Subaru All Wheel Drive system works! Thanks!!

Great explanation of how Subaru and works thank you .

Very well explained on topic that is complex into very simple to understand language. Thanks Alex for this informative video.

Thanks for explaining. I love my Forester.

Very well explained sir, enjoyed your explanation so much.

Torque split depends on the transmission, model, and year. For example, Gen 3 Outbacks have ~41/59 Front/ Rear. Gen 2s (and the Baja) were mostly 45/55. Imprezzas are all over the place.

Well explained. Thanks for sharing all that knowledge

Really enjoy your channel a lot. All other automotive reviewers out there: TV, magazines, RU-vid included loves to rave and kiss a$$es. You have always been very clear of your personal unbiased views. Not only that, you have demonstrated you have thorough knowledge of automotive engineering. To top that off you are a consummate presenter also. You are an excellent editor or do you do all of your videos in one shot?

I like this channel. I'm studying English. I like cars. Really helpful explanation and so fun! Thank you :)

This was a great video!

Well done Alex.

Loved the video!! Any chance of a Levorg review??

Great explanation. Could you make a video explaining the Haldex AWD if you haven't already?

Thanks Alex it was awesome explanation,

Nice video Alex

What would be interesting to know is how exactly the brake system working to stop the slippery wheels.

so nice explanation: handy and comprehensive. Thanks,,, Subaru is my Love

Got a question. what are front and rear differential types? I watched a video from subaru and it says that they shift power front to back(which I get it bc you explained it here) and also side to side. With front or rear differential being open, how does subaru achieve side to side torque distribution? Maybe they are not open diffs?

Excellent - very clear.

Thanks for the video. Nice one. I am looking to buy the Forester. Can you say how much difference in 2.5 & 2XT options?

great video, today I jacked up my 2011 outback 2.5 in the air. I shifted to D gear. but only front passenger side and rear driver side wheel spin. is that normal?

Excellent video! Cheers mate!

Alex - I am looking at two CVT SUVs. I put a lot of miles on my car for business, something like 20,000 a year at most, 15,000 a year least. I am concerned that the CVT transmissions won't last beyond 100,000 miles before needing major overhauls. I currently drive a Jeep Commander with almost 200,000 miles on it and with no issues with the German made TipTronic 5 sp automatic transmission and Jeeps QT-1 all wheel drive system. Can you shed any light on the long term reliability of these CVT units? My thanks.

As an Impreza freak and proud owner of a 23G ice blue WR1 (one of only 500 released in the UK), this was a great explanation of why my beloved car can cut it in adverse conditions even with low profile, non-chunky tyres. I don't race around in it like a dick and knowing how to drive in all weathers helps a lot. I am mostly an idiot re what's under the beautiful exterior. Thanks you!

I have a 2011 impreza 2.5i wagon auto for my work car. I live in the mountains and get alot of snow on our interstates before they plow. I bought it used right at the end of last winter and only got to drive in snow once. if i remember right it wanted to fish tail. is that because of my torque split? or could it be bad tires or the light weight of the wagon in back?

Why does the TFL up hill on snow show the Subaru failing when the steering wheel turned? and the CX-5 passing the test?

Could you please do a review of the AWD systems in CRX/RAV4/Rougue just for comparison sake? Thanks.

You know, I had no idea such a pedestrian car had such a complicated drivetrain. Good info, Alex.

subscribed! very knowledgeable!

Can you please review and explain the quattro system of an Audi RS3? It is different from the one in an A3.

Thanks Alex!

Alex, can you explain how the current Hyundai and Kia awd systems work compared to others with pros and cons. I believe that the HTRAC and Dynamax aren't slip and grip systems. How do some systems work better on road or off road and how transmissions make a difference as well. CVTs and DCTs can overheat off road I understand.

question ....if my subaru forester (sf5 1998) is missing one front right drive shaft will it move? for how long will there be damage??

Hey, great presentation! I've been reading about the workings of Subaru AWD off and on for years, but there are a few lingering mysteries that none of the sources address. What is it about the type of transmission that dictates the type of AWD system? Why does it makes sense, from an engineering standpoint, for manuals to get a viscous coupling while automatics get the multi-plate clutch? It seems there must be some mechanical reason, or else it would make economic sense for Subaru simply to deem one system "better" and use it universally (other than special cases like the STI). And if the MPT, under normal conditions, is sending some power rearward without locking completely, doesn't that mean the clutch plates are usually intentionally slipping a bit? How does that not quickly wear them out?

Does this info still hold true with the new auto with CVT(continuously variable transmission)?? Thanks Great video btw!

HI Alex.. great video. i have question. I have 2014 Forester, installed 235/60 R17 yet the spare wheel is the original factory wheel which is smaller in diameter, if I install it, well the AWD light flashes? if so, will it damages the transmission?? I saw some video people install a fuse in an empty slot in the fuse and the FWD light comes on, I tried all empty fuse slots, the FWD light never came on. appreciate your kind advise.

I have an 03 Forester, at a complete stop on slippery snow road, when I accelerate the front tire spins in the snow then about 1 sec of spinning the awd engages, is that normal?

Ok, this must be an older video. So what will the 2018 Subaru Ascent have in it. Thank you. Roger

Isn't Subaru's ABS system playing a significant role in torque distribution? I drove an Impreza for a week in icy town and road conditions and was impressed at how the brakes were quick to slow the spinning wheels, compared to my '12 Rav4 for example.

are the late 2000 outback and forester models engines like this? centered?

When the Subaru multi plate clutch locks up, does that mean it's 50/50 front/rear? Can it send more than 50% to the rear?

manual Subaru's have a center differential in conjunction with the viscous coupling. A system with only a viscous coupling would only send power to the rear when the front are spinning

I'm confused, from what I know the the CVT models have viscous center joint with no Differential and Manual has Third differential and locking clutch pack.

Ok so I have a 5 speed 09 outback xt. I watched the guy from Engineering Explained go through all the subaru awd systems and I could understand why the ones for the sti and wrx were designed the way that they were, but I don't understand why the manual and automatic here are different? Is there a reason why the manual transmission subarus Need to have the viscous coupling setup vs what they have in the auto or is it just something that subaru did randomly? Is it because they think less people buy the manual versions anymore /or they don't make them entirely and so they see no need to update the mechanics in those models?

My Subaru outback is a 15 and my all wheel drive is messed up and it only front wheel drive now what is wrong you think

My 2015 impreza 2.0i 5 speed manual has 50/50 awd

Excellent description, learnt a lot. My question has a strange twist, I know the basics of AWD and am verse on 4WD, so I know the technical differences. I am looking to get a more family oriented vehicle which would be the Forester. But I want to know from a practical aspect, for light to mid offroading, say beach and camping, how would the Subaru AWD systen compare to say a Vitara with which is a 4x4 with high and low range. Thanks..

Wow! Great explanation; very easy to understand. I've always wondered how Subaru's system differed and now I know. Just one quick question: how much maximum torque can the Active Torque Split system send to the rear wheels?

I believe another advantage over other "slip 'n grip" systems is the fact Subaru's AWD has torque vectoring and can send most if not all power to just one wheel. In extreme cases should only 1 wheel have grip, it's been proven than Subaru's AWD can pull a car uphill with just one wheel, where most other AWD systems fail. Subaru doesn't mess around. It's the best and most practical AWD system out there, I feel.

How difficult can you explain something very simple? You have done it! Congratulations!

I currently have a bad driveline in my 05 outback manual transmission I'm wondering if I can run it without the rear drive line maybe half of the driveline can anybody out there tell me if it will work or if I will hurt them clutches

hello i have a 2007 forester 2.5 non turbo automatic, the locking solenoid seems to have all the wheels locked, i have a grabbing feeling and rubbing sound when making turns, no transmission or abs codes, any advise would be greatly appreciated

So what about a 07 impreza auto trans.. Bigtime binding in a turn..thx

What about the other diffs? what thype are they?

Great Video. But I own an 2014 Forester with the cvt. So let's say I'm in a slippery condition. You're saying that my car would have 60/40 split instead of 50/50 ?

Nicely summarized. Though the 2015 Outback 3.6R is now HT-CVT equipped, so should behave awfully close to the Forester XT's 60/40 setup.

04-05 STi splits 35%front 65%rear 👍

can you compare the subaru awd system with acura sh awd?

Thanks for the lucid video. I wonder if you can help. I am trying to diagnose a ticking sound coming from the bellhousing area of the drive train on my 97 Subaru Outback. When running at high speed, the tick in inaudible, except on deceleration. The sound is most pronounced at idle. Listening from underneath, the sound appears to come from the bellhousing area.(The car is AT) From the area of the flywheel that is visible, the flywheel appears to be burnished in comparison to that of my other 97. I thought that maybe a stone or something found its way into the bellhousing because there is no cover for that space. (If the stone were trapped, centrifugal force would keep it stationary at high speed.) I made a chalk mark on the balancer and manually rotated the crank. A pronounced clink occurs at the same spot with each rotation. I had a friend rotate the crankshaft while I lay underneath. The sound came from the transfer case area on the driver side. When the crank came 360 degrees from my mark, I got the same sharp click, like a drop. At 180 to my mark, there was always another barely audible click. (like something re-setting at 180 and dropping at 0/360. I should mention that the car drives well with no signs of diminished function in any area.

You're telling me the manual transmission subaru never has a 100% direct connection to the rear wheels? If so... that explains a hell of a lot of why the car feels "dead" and "souless" compared to other MT car's I've driven. I was wondering wtf was up.

I am building a dune buggy with a 2000 2.5 non turbo Subaru standard transmission. How can I transfer all power to the front wheels.

The picture at 1.24 is incorrect. 1st the engine is very low and wide and the drawing is spot on but it should be rotated 90 degrees. 2nd the gearbox is pretty long and starts where the windscreen is and goes all the way to the backside of the front seats, which means that the actual driveshaft at the back is pretty small -) Next time provide the pics of the car and gearbox! Another thing to mention is that the TZ gearbox provide 90% to the front and 10% to the rear as a normal drive and able to shift to 60/40 if needed, also in the manual mode (1st gear) they can operate at 50/50...

How does Subaru send all the power to one wheel if it has a traditional rear end? I thought I've seen a video showing a Subaru on rollers where one wheel had traction and it climbed up.

I have had a Subaru forester 1997 (automatic) from new (approx. 70,000 miles on the clock), that has been great for all the years with very little to do other than annual services. However, recently I have had a lot of vibration & shuddering on the wheels when making slow tight turns (left or right) but never on the straight. It is difficult to identify which wheels the noise or shudder comes from and I don't feel much through the steering wheel. I have had all differentials replace that has reduced the frequency but not eliminated the problem. We hope it isn't the automatic gear box but has anyone got any ideas what to do next.

I've been a Subaru driver for most of my driving life and there really is no substitute for their AWD system and winter tires. I've driven other AWD cars and as silly as this might sound. There is a reason why Subaru used the liquid to semi-solid system rather than computer controlled systems. Don't get me wrong all cars should have some sort or AWD system especially with the silly amount of HP that most cars seem to have these days.

U should have explained how it transfers torque from front left to front right!does it have a EBD using open diffs and ABS or has it got some diff locks but overall the movie is good!

Forester Manuals are 50 50 split Normal driving. There is no front wheel Bias. The Manuals have a true center diff, the vicious coupling only come into play if there is slipping

How to engage 4WD in 2002 subaru forester x20 automatic

around 6:15 Slip&Grip-Style System reapeats itself sthgs wrong?

hi Alex, if you have to choose between a Subaru flat 6 and turbo 4, which one would you pick and why?

How is it that the clutch packs of other manufacturers (like Nissan) tend to overheat even though they are rarely engaged yet Subaru's never seem to overheat even when flogged, and is always engaged?

Hi Alex, just out of curiosity, which AWD system is the best for winter driving between Subaru's, Acura's SH-AWD and Audi's Quattro? Would it be reasonable to say that they are about the same?

Sorry, didn't get it, speaking about Subaru Outback 2015 model year (new gen) what system 2.5 has, what 3.6 has, are they different? Are they 60/40? Is for Forester the same? What is better viscous coupling or multi plate clutch and why? Thank you for the video!

What about the transfer of power from left to right on both front and rear axles?

Alex on Autos I haven't seen a 2015 Outback review from you. Can I assume it's not on the schedule?

I'm confused... 1. I thought the transfer case is what separated AWD from 4WD. 2. Do both Subaru's automatics and manuals use the same power distribution method? 3. If power distribution is almost always 50/50, doesn't that cause problems when turning?

manual trans Subarus and XT models are 50/50 split

Are you sure that 60% front/40% rear applies to manual transmissions? I know my 01 Outback manual is 50/50 in all conditions. That said, there is one downside to having the transfer case built into the transmission: If you experience binding in the transfer case, you can't simply replace that part. You have to replace the entire transmission. I've gone through two because of failing transfer cases. (I know I should have sold the car after the second one died but for reasons I can't get into here I can't simply get rid of it).

So in a 2005 WRX it has the viscous transfer case behind the transmission, but you said they program it to be 50/50 by default? I wanted them to do that AWD test on an "older" manual transmission car but I just can't find it.

I am confused. In my 2013 forester manual 5 speed the AWD system works like the 4WD system on my truck... power to the front left tire and rear right tire.. difference being 4WD has locked hubs with a LSD or a locker in the diff.. AWD having open diffs using the same setup but computers monitor wheel slip, if slip is detected it then redirects power to the opposing wheel through a clutch pact. I have performed many tests on ice and proved that is how my system works.. the power split on my Subaru is 41-59 and if needed it will do 50-50.. I have never experienced a situation where my power split was 60-40.. the front tires usually do not slip first except if the front tires have no traction but rear tires do..It is always the rear tires that slip first for instance on a frozen lake or a sheet of ice at a intersection the majority of the power goes to the rear and the rear kicks out until the front wheels have caught up in wheel speed. While I am cornering I apply more power and the rear kicks.. If what you are saying is true about 60-40 split then i should experience under steer or feel the front slip during hard acceleration right? Am I misunderstanding something? How I have felt the car drive and what you are explaining do not match. Did Subaru change their design between 2013-2014? Even a certified Subaru mechanic has explained to me that my forester has a rear bias and if needed can even the power between the front and rear but never front wheel bias. Now other vehicles i have driven that have a setup such as the CRV I for sure felt under steer while cornering and front wheel slip during hard accel... which would make sense that the CRV has a 60-40 split. But I have never felt under steer in a Subaru cause of a front power bias, if under steer happened it was the drivers performance.. I bought Subaru over Audi, BMW, Honda, Acura and all the other companies selling AWD because I was told the Subaru AWD was not a front bias setup. Last thing I might add is I have a controller that allows me to manually choose power between front and rear.. like what you find in the WRX STI.. I can never do a 60-40 split. It is always between the range of 50-50/21-79. But even on my buddies Forester without the controller he still has a rear wheel bias. I appreciate the video, I would love to hear back from you with your thoughts.

Hi, I have a couple of questions. Is the multi plate transfer clutches in a oil bath or something?! What is preventing wear and tear of the clutches? Can they overheat and if yes, is there usually some sensors for that? I read elsewhere that the CVT in the 2015 Outback (and others) is not designed for engine braking. Downshifting with the paddles will increase wear and tear on the CVT. Is this true? If you are for example spinning on ice and suddenly "catch" some tarmac, what is preventing the shock from destroying the CVT cones due to slippage? I recently tried a Outback 2015 - the electronics limits the RPM to prevent strain to the CVT (as I understand it). I am unable to climb steep hills and even a simple diagnoal test (uphill) caused the outback to simply not move at all. I wonder how weak/strong is the outback in case of towing a trailer uphill (especially when starting). I supposed you can't add much weight when the car is incapable of moving itself without load. I live in Norway so the only Subaru I would consider buying is the Outback 2015 2.0 diesel. More details on this is appreciated :) (thanks for a nice principles of operatoin explanation).

In our 2013 Outback 3.6R (traditional tranny) I've been under the impression that the split is rear-wheel-biased 45/55 (front to rear). Is this referred to as Variable Torque Distribution on my particular model year? Am I correct or did I miss something while doing research? By the way, great explanation on the AWD system. The following is copied from SOA website: Variable torque distribution AWD: An AWD system designed exclusively for 5-speed automatic transmission, E-5AT (with manual mode) models to provide aggressive, sporty driving with increased turning abilities all while retaining the fundamental driving stability offered by the Symmetrical AWD. An uneven 45:55 front and rear torque distribution has been set for the front and rear tyres. Sending greater torque to the rear wheels can reduce understeer, a trait that plagues 4WD vehicles, when cornering for smooth and agile handling. Torque distribution is controlled automatically up to an equal 50:50 front and rear to suit road surface conditions for both sporty driving and stability.

Hello! y own a Subaru outback station wagon 2003 with a h6 my rear whells are very hard to turn wen on the lift y change the rear bearing redid my calipers y still dont anderstand also lousend my hand brake cables excuse my English rithing im french thank you in advance

this is why subaru has THE BEST awd system!

Alex, you're saying "power" when I think you mean "torque." Perhaps define those two terms upfront and use an example that the torque any wheel can receive cannot exceed what traction it has, and that power = torque x speed. I think also the location of key components is not relevant to the theory of operation, despite Subaru's marketing. Best to define the terms, define the typical components, discuss the theory of operation using those components in the various models, then describe where components are located in Subaru's implementation. Thanks for your efforts!

So is my 2013 Legacy 3.6 R a Muti plate unit vs vicious?

Doesn't the current WRX have a rear wheels bias (more power to the rears) compared to this car you're reviewing?

Since you seem to know your stuff do you know what system the 2015 Legacy 3.6R has?