A Subaru with a Toyota Hybrid System

See the amazing TH2A transmission of the 2019 and above Subaru Crosstrek Plug-In Hybrid Electric Vehicle (PHEV). This all-wheel drive (AWD) vehicle and transmission use the impressive Toyota Hybrid System (THS). A special thank you goes to Subaru of America for the vehicle donations and support for technician training at Weber State University.
TIMELINE:
0:00 Start
0:07 Introduction
1:26 Integrated Toyota Hybrid System (THS)
2:37 Mechanical All-Wheel Drive
3:20 A 2019 Toyota RAV4 P710 Transaxle to compare
4:30 Motor/Generator 2 (MG2) Rotor and Stator
5:08 Motor/Generator 1 (MG1) Rotor and Stator
6:00 8.875 kWh High Voltage Li-Ion Battery
6:14 Electric Vehicle (EV) Driving Mode Components
7:00 MG2 Torque and Power Specifications
8:12 EV Driving Mode Operation
9:23 The front differential ring and pinion gearset
10:33 MUST SEE: EV Driving Mode Power Flow
11:18 Hybrid Electric Vehicle (HEV) Driving Mode Components
12:09 The three functions of MG1
15:33 HEV Driving Mode Operation
17:44 MUST SEE: Obtaining Continuously Variable Transmission (CVT) Gear Ratios
19:45 MUST SEE: Three Types of CVTs
20:30 See the combined gear stack for EV and HEV operation
24:18 Parallel Hybrid operation and Series Hybrid Operation
25:55 Front-Wheel Drive is the default mode
26:20 Additional Components needed for All-Wheel Drive (AWD)
27:27 Electromagnetically Activated AWD Clutch Pack
29:57 MUST SEE: The Ball Ramp Clutch Actuator for AWD operation
32:33 See the two shafts the AWD clutch connects together
34:42 See the Complete combined gear stack for EV, HEV, and AWD operation
35:16 The oil pump
36:28 MUST SEE: The complete transmission assembly and cutaway operation
39:55 Video Summary
ABOUT US
Weber State University (WSU) - Davis Campus - Department of Automotive Technology - Ardell Brown Technology Wing - Transmission Lab. We teach current vehicle technologies to our automotive students at Weber State University and online. For more information, visit: www.weber.edu/automotive
This video was created and edited by Professor John D. Kelly at WSU. For a full biography, see www.weber.edu/automotive/J_Kel...
ADDITIONAL TRAINING FOR YOU
Join us for hybrid and electric vehicle training with two online courses and a 5-day on-campus boot camp with Professor John D. Kelly. See www.weber.edu/evtraining
DONATE TO OUR DEPARTMENT
Please consider a donation to the Department of Automotive Technology at Weber State University here: advancement.weber.edu/Automotive

[@charlesdeblanc3386]

As a Subaru tech, I found this very informative! I wish they would make more of these, as the eCVT through gear action is much more reliable than the pull chain CVTs in all of our other vehicles. PHEV is a great transition to full EV adoption as it gradually increases the load on the power grid for charging. Thank you professor, I enjoyed the video and the cutaway transmission.

[@ThePilotGear]

totally agree with you

[@user-uv8nk2fn4u]

To help avoid the disaster of the total electric grid collapse if and when the incorrect politically mandates in the future hybrid vehicles are the intelliigent realistic choice.

[@av8bvma513]

O*U*T*S*T*A*N*D*I*N*G*! A model demonstration, clear, concise, accurate, logical, and on a personal note, I found it quite delightful! Thank you very much Professor Kelly for showing the rest of the world how it is done!

[@WeberAuto]

Thank you so much!

[@fabrisoto]

👏🏽👏🏽👏🏽👏🏽👏🏽👏🏽

[@wgmskiing]

This is a really neat application of the e-CVT. The cutaway you and Nash put together is fantastic. Thank you!

[@WeberAuto]

Thank you, I will tell Nash.

[@alexmoralessmith385]

This guy is absolutely awesome teaching... At beginning didn't want to watch the full but after the second minute I didn't want to stopped he made so interesting

[@supermotos]

All these years later since I first started watching this channel for technical information and it's still masterclass stuff! Better than ever actually.

[@WeberAuto]

Thank you very much Rick!

[@The_Uranium_Imranist]

Hi, Professor John Kelly, I would like to salute you, your hard work and explaining style. Actually you teach like a respected primary school teacher which is amazing for me. I am a civil engineer but now I know many things about mechanical technology specially EVs and their transmission systems. Keep it up, be blessed with such teaching power. Thank you.

[@161995alex]

Thank you John Kelly for all that you have done through the years. I just noticed in the GM emerging issues that you have been a GM world-class technician for over 20 years. I want to thank you for sharing all your knowledge with us! I love learning about hybrid and electric vehicles so I am very thankful for your videos.

[@WeberAuto]

Thank you Aaron!

[@donavan2517]

You're putting more effort in editing the videos and it really shows. I like that you've made it look a lot fancier yet not changed the base style, makes it feel much more personal and genuine. Keep it up.

[@WeberAuto]

I appreciate that!

[@seanpquinn]

My wife and I each own one of these vehicles (2022 and 2023) and love them. There does seem to be something special about them and watching your video shows one more reason why. Thank you for the education! I’m always trying to learn more about this new world we all live in.

[@ByrdNick]

The CVT distinctions, ball ramp demonstration, and cutaway were most helpful. Thanks!

[@ouch1011]

Fascinating video. These Subaru hybrids seem to be incredibly rare, so even during my time working at a Japanese car specialist, I’ve never worked on one of these. I just assumed that, given Toyota’s substantial influence on Subaru and their recent parts/vehicle sharing, Subaru was using a hybrid system with a similar design to the THS. I did not expect it to be basically an exact clone, just repackaged for the unique drivetrain layout Subaru uses. I’m also surprised to learn that the older Subaru hybrid vehicles were parallel hybrids. I look forward to seeing a video on the older setup. Honestly, if I were in the market for a Crosstrek, I’d be much more interested in the PHEV version. The light-duty Subaru CVTs are trash, the power split CVTs like the THS uses are practically indestructible with basic maintenance. The AWD system looks to be very similar in theoretical operation as the system they’ve used in their automatics since the early 90s. The system has always been electronically activated, and they’ve always been FWD if the AWD actuation is off. They used to call it the transfer clutch. This one is different from at least the old 4 and 5 speed autos (and I assume the CVTs) in the sense that it is fully electromechanical. In the 4 and 5 speeds (and probably the CVT) it is electrohydraulic, using a solenoid to control fluid pressure to the transfer clutch (just like any other clutch pack in an automatic). Makes sense that they would make this an electromechanical system instead since this style of hybrid system does not necessarily require a high-pressure fluid pump like an automatic or CVT would.

[@RotoRCol]

just curious what did you study since you worked as a Japanese car specialist?

[@WeberAuto]

Thank you, and thanks for the information.

[@danb708]

Dr Kelly -- You are a truly talented instructor! Clear, complete, and concise!

[@Wladywostock]

Every body realize that Synergy drive and plug-in from Toyota Prius is a genius design 😎 Thanks John.

[@WeberAuto]

Thank you!

[@justinmijnbuis]

such a great channel! Thanks Professor for all those great masterclasses over the years.

[@JohnDoe-ti6pd]

Big Thank You prof. Kelly (and of course assistant Nash), this is the best explanation of Subaru PHEW AWD drivetrain I ever seen.

[@edrumsense]

What an impressive video, I was impressed about this technology, now I am in love of it. This system is so simple yet so smart made.

[@beforebefore]

I was weirdly STUCK to my TV screen watching this specific video... the rear drive clutch is a truly fascinating engineering design... using a low power /low torque electromagnet clutch to trigger a high-force mechanical "ball-ramp" actuator that utilizes the high-power system to actuate the "real" clutch-pack... so cool! Apparently as the clutch friction disc's wear and become thinner, the balls will travel farther up the ramp to compensate for the wear... nice. I design small electro-mechanical systems, I'll have to remember this trick!

[@belferragadel2629]

Thank you for the simplified explanation. Although it is complex, it differs from the previous Toyota hybrid system. However, re-explaining several times is easy. Thank you

[@shanesnyder7359]

Exceptional demonstration! Thank you for your enthusiasm and willingness to share your talents. 👍

[@jakemartin4305]

Amazing how rhe "NEW" is always just an inovation of old tech that transmission looks just like an old manual gear box with electric motors an amazing video thank you for your servive 👏👏👍

[@zubeyircimen6205]

Thank you for your distinct videos explaining driving technology meticulously. Looking forward to more videos.

[@mohammedsuboh1420]

You deserve to be a professor, but more than that because of your simplified explanation and your great knowledge

[@MarioDallaRiva]

Very impressive! Super job on that cutout of the case. I’d recommend auto journalists watch your channel. They will learn why this CVT feels so much better than the ‘older’ CVTs 😎

[@Miata822]

I have recommended this channel several times to specific journalists after reading errors in their work.

[@WeberAuto]

Thank you very much!

[@MarioDallaRiva]

@@Miata822 right on, Bill 👏🏼 Professor Kelly is the best, without a doubt. Just look at all the P-Touch labelling! Details, details…

[@babaganoosh555]

Good luck. Motoring "journalists" these days don't seem very interested in understanding how cars work beyond the interior of the cabin 😒

[@av8bvma513]

@@WeberAuto I have recommended this video and sent links to three automotive technicians that I know.

[@HASANESEN]

Your shares are very valuable. I congratulate you for your hard work, professor.

[@s.m.whiteII]

I purchased a 2013 Ford Cmax PRIOR to discovery of this channel. And I SOLD it based on the information from this channel. The car still operated ok at 138,000 miles, but based on this channel I felt either the CVT or the battery pack were on borrowed time. I didn’t like how violently the car shook when the gas engine started when cold. Even after a spark plug/coil pack change, it didn’t improve much(was still running original plugs/coil packs). I sleep much better now😁

[@madlucio70]

Great video! Thank you so much for breaking all of this down in such detail! I own a 2023 Crosstrek PHEV and absolutely love it. Great to see what is going on inside.

[@WeberAuto]

Thank you!

[@madlucio70]

@@WeberAuto My pleasure! I can drive all around Montreal on an 80-90% charge typically since there are a lot of lights and traffic. The regen braking and "B-Mode" down hills and coming to stops squeezes out a little more range each commute. I never use petrol in the city and the Atkinson' cycle boxer gets me between 6.5 and 7.5 L / 100km mileage on my weekly 400km roundtrip that I must do to and from Gatineau. This is quite impressive considering I always make this longer trip packed heavily (clothes, tools and camera gear) with both my bike and kayak racks on the roof. In other words, I am not driving long distance efficiently as I am adding considerable weight and significant drag. This route is also prone to very heavy winds and yet my mileage is still really good. This vehicle is truly a fantastic example of great AWD technology and it keeps me safe in all weather (heavy storms, snow and wind) and lets me go off road or bum about the city :) I am even trying to document my PHEV life a little bit for others who might want to take the leap into PHEV's or even full EV's: raven7818.zenfolio.com/blog It is not even close to how informative that your video was in just 40 minutes, but it is enjoyable to do when I get the time!

[@madlucio70]

@@WeberAuto Really love this video and have watched it multiple times through! I have a question about the oil pump since I want to care for my PHEV in the best way possible. I live in Montreal and it can get quite cold (-25 C at times) and when I do things like hit the highway or turn on the defrosters the Boxer will kick in when I am in EV Mode. My question is this: Does the Oil pump pre-prep the boxer engine at all when I am driving in EV mode only? I ask this since I find it a bit harsh that the Boxer will kick in "cold" while driving in EV mode under these specific conditions. When this happens, I force it into charge mode until the motor warms sufficiently and only after that drop it back into EV only or Save Mode. If the oil pump is circulating oil through the actual motor, even when only under EV drive then that would explain why the Subaru can support starting the engine mid-drive. Thanks for your time and great explanations!

[@BenHuttash]

You make incredible videos andI appreciate what you do. Every video is a masterclass. Thank you for what you do and I hope KZbin is kind to you because you are giving away years and years of training and education with every video. Saint like automotive education charity you offer to the world.

[@WeberAuto]

Thank you so much!

[@Cruzerak]

Thank you ! You do such a good job explaining how things work, always love your videos.

[@geoffcrumblin7505]

Very impressive presentation. You have allayed all me fears about going this way.

[@3SPR1T]

What a great way to learn about new mechanical methods to transmit a power band... I'm a mechanical engineering student from frankfurt germany and I feel privileged to have such great professional source of information just one click away. I hope I can take a visite some day.

[@olafk2297]

I love your explainings, good to understand. Thanks Professor Kelly

[@53ricci]

Great video professor Kelly 👍🏼 Really enjoy watching these and still miss being in class!

[@WeberAuto]

Thank you!

[@ismaelcruz3315]

Thank you, Professor Kelly, you make it interesting and easy to understand.

[@rsearchtim]

This was a great video. I never knew that Toyota owned part of Subaru. I also never knew/seen an electric (or magnetic) clutch. Great Job!

[@pcxxy]

Amazing video save explain. And genius design of the cvt system that avoids all the reliability problems with few belt version

[@knuth.degaard2236]

Absolutely great education! Still wainting for your next video!

[@MrSvetlin09]

Thanks a lot for your work. Very interesting and professionally presented content.

[@techquirks707]

We all appreciate what youre doing. Well explained as always. Thank you for your work.

[@WeberAuto]

Thank you very much!

[@ElAnciano92071]

I love your very instructive videos, and can hardly wait until you get your hands on the 2023 Prius and Prius Prime! ;)

[@daru666]

@WeberAuto I just like cars. I have not school on mechanics. But You are a wanderfull Teacher. Thank You

[@AndyM...]

Hi Professor, just want to re-iterate most other comments regarding your excellent explanation and presentation on this transmission. I'm an ex-mechanic and remember pulling apart manual 3 speed transmissions which only had 5 or 6 gears in total and were so simple. Hats off to the mechanical and electrical engineering team of these types of transmissions that are able to get complex systems seemingly working in harmony. Thanks again and really enjoy the content you and your team create !!!!

[@WeberAuto]

Thanks for that!

[@tjadventures]

Great explanation, you seem to be a really good professor, really nice video!

[@Thegonagle]

Hey Prof, thanks for yet another great disassembly video. I hope you enjoy making them even half as much as I enjoy watching them. BTW, I like the new graphics! 🖖

[@WeberAuto]

Thank you very much! It is a lot of fun for me to explore these. Thanks for the feedback on the graphics too!

[@rayleblanc7121]

Awsome Introduction to the ? electrtic tr580 , Very Well Done Sir

[@lpolityk]

Thank you very much. Very much informative, explanatory, easy to understand.

[@Marker-er3ro]

Awesome video and explanation! Thank you.

[@dbascb]

Incredible video, watched it twice. Thank you

[@dc33333]

my favorite professor. Thank You for the video!!!

[@gevorggevorgyan1244]

Again and again good cognitive lesson. Thank you professor John Kelly -you are my distance learning teacher. if possible make video abot Volksvagen ID4 and ID six please . Watching all your videos-Take care dear mr. Kelly .

[@WickedTRX]

I really like the transfer case solution! It’s like an electrical relay, it would take an enormous amount of energy to squeeze the clutch pack directly, instead this solution uses a small clutch that regulates the ramp system that uses the output torque from the transmission.

[@WeberAuto]

Thanks for your feedback!

[@brianb-p6586]

Yes, it is servo actuation approach.

[@Wolfox360]

Wonderful, interesting video as always. Still waiting for the day I will see the Lexus IS300h transmission video :)))))

[@UD503J]

I wish we could find one of these in our area. We love our Impreza and have previous experience with plug-in hybrids and it'd be great to get an awesome combo of both of those.

[@bluedog8269]

Love how you can do this without getting your hands dirty!

[@erik_dk842]

New and cleaned parts

[@hmtperftthh6064]

Excellent video Professor Kelly!

[@rkymtnrsx]

I have the 2020 Crosstrek PHEV. It has been a great vehicle. I have over 73k on it and it has only had oil changes, filters and tires. I average about 60 mpg over a tank of gas and sometimes go 715 miles between fill ups with very low electric charging cost. I use 120v at home and slightly faster charging at charging stations.

[@WeberAuto]

Thanks for sharing

[@TheYonderGod]

I can't find actual specs anywhere, could you answer my questions? What is the battery only range, and what is the actual MPG after the battery is depleted? You can easily figure this out by starting a trip odometer after the battery is dead. I'm wondering because I have a Chevy Volt and it is far from the advertised specs, because of course it depends on how long your trips are and how often you charge. You can't give a PHEV a generic MPG rating like that.

[@rkymtnrsx]

@@TheYonderGod The advertised EV range is 17 miles, that’s what it will show available unless you turn on the heat or a/c, in which case it will show 15 miles range. You drive a mile before the capacity drops from 17 to 16 so in my book that equates to 18 miles. If I ran by battery down and just continued under gas/hybrid mode the advertised mpg is 30-35mpg. That is what I usually get when we take the car on a trip of several hundred miles. I am always looking for a free place to charge along my way even though this car has a slow charging speed. It takes about 2hrs 10min at a level 1 charging stating for a full charge; the last couple miles take the longest to top off. I charge whenever I’m at home so over a tank of gas my average recorded mpg tends to be anywhere from 50-70mpg. It varies greatly depending on daily miles and route.

[@TheYonderGod]

@@rkymtnrsx thanks, that's the info I was looking for. Crazy that nobody has improved on the technology from that came out in the Volt 10 years ago, other than the small upgrade on the gen2 in 2016.

[@donswier]

@@TheYonderGod 😊👍 When I test drove used Volts (great car BTW!) one car had lifetime average of 39mpg, and the other's lifetime was 260mpg. Guess which one was a fleet car for an insurance company? The other was privately owned & garaged nightly. I ended up with an i3 REx. 24k miles on 25 gallons last year. 1 speed series hybrid. PHEVs & range extenders are great.

[@MrWilliam.Stewart]

When Professor John talks, I learn. Thanks man.

[@WeberAuto]

You are welcome!

[@ghostindamachine]

What a cool and informational video :) Really awesome!

[@derick3282]

Really find your videos interesting. Thanks a lot.

[@jayantajithazarika2619]

Thank you very much for your nice and fàntastic video . I wish you a very Happy New Year , 2023 ! With lots of love and regards , Jayantàda , 31/12/2022

[@cheungpaul9483]

amazing video with so much details. Thanks

[@Bgkim1113]

Thank you Prof. Kelly again

[@MarioDallaRiva]

Great to see you, John! I was literally just watching your Honda E-CVT video (again) and this Subaru video appeared 👍🏼 Awesome timing, thanks.

[@WeberAuto]

Cool, thanks!

[@bobpurcell5662]

Excellent clear-cut and simplified (as much as possible) explanation of this transmission. How much of the transmission components are bathed in oil? Is the rear drive a dry clutch?

[@HandyDan]

Another amazing video John! We recently bought a 2022 KIA Sorento PHEV. I would like to see a video on the transmission. I have driven the 2017 Chevy Volt PHEV, and A 2020 Rav4 Hybrid, but the 2022 KIA PHEV Sorento is different. I notice that in EV Only mode it still shifts the 5 speed Automatic transmission, Kinda neat as this gives plenty of torque in 1st gear and also eases the RPM at highway speeds. MFG states 32 miles on EV, but in Phoenix with the A/C on driving the freeways I can go 37 miles on EV only.

[@WeberAuto]

Thank you and Thanks for the suggestion!

[@nathanmrg2]

Professor Kelley, outstanding video of the highest quality. If you get time, could you please do the Corolla Cross Hybrid? There's a lot of information I would love to learn about the eAWD system (amount of torque split and such) as well as the smaller Toyota 2.0L hybrid system used in the newer Prius, corolla, and corolla cross. My frustration with trying to own/purchase one of these was Crosstrek Hybrids was the dealerships lack of support with these on maintenance but also parts. If you didn't live in CA or OR in an emissions control state, Subaru dealerships would not do any basic maintenance on them. Worse was trying to find parts for them in 10 years as Subaru is notorious for upselling the parts and the availability of these would difficult to find. I went with a more affordable Impreza as it seemed reliable even though I do not like the CVT system compared to the newer direct drive ECVT. They rolled out an awesome package but the Subaru North American support for the maintenance could have been better.

[@WrightLisgar]

Great video. Thank you.

[@Stefan_Dahn]

Donated 50 € for your superb videos enlighten us with engineering insights! Best wishes from Germany! 🇩🇪❤️🇺🇲

[@WeberAuto]

Thank you very much!

[@pt4958]

Thank you Mr. Kelly

[@dbascb]

Incredible, Thank you

[@lLisanderl]

Thanks for the explanation, it's really interesting. Could also you make a video about hyundai\kia hybrids ?

[@cirros124]

Thank you very much for this video!

[@aorr]

This video is incredible. I’ve learned so much. I’d like to highly encourage you to do the 2016 Crosstrek Hybrid as you mentioned you’d do so I can learn how that one differentiates. Well done! This is *so* informative. I’m coming from a non-mechanically inclined mind but watching this just to learn how the Subaru/Toyota hybrid systems work.

[@WeberAuto]

Thank you!

[@engamen87]

Such a great Instructor

[@user-qw1wx2zv3c]

I 'm watching you video from Ukraine. Very cool. I'm bad undenstanding, but I'm learning English.

[@WeberAuto]

Thank you!

[@lasithrajamanthri5992]

Man your shop assistant is a lucky

[@WeberAuto]

Thank you!

[@kathmandun8749]

Excellent video

[@user-zz6zk8tb7c]

Awesome. Very similar to the Lexus GS450h hybrid gearbox, but instead of a neat spragge clutch to drive the oil pump from two sources it uses an electric oil pump for electric only mode.

[@joshpiatak7919]

This video makes me want to get into drivetrain engineering

[@FedericoTesta1]

It's quite an impressive configuration. More than the regular toyota one

[@Hp2G1]

Thanks for the video, very informative. I have one question. How does the reverse work on the e-CVT? I don't see how it can be provided through gear action. I guess it must be provided by the electric motor/generator Number 2 only? Very ingenious transmission, and very clear explanations. Thanks.

[@paulaxford6754]

Thanks, John, there's nothing else like this on KZbin! I've been a fan and student of the HSD from the beginning and frankly can't see how it can be beaten for efficiency by any other hybrid system. This Subaru application follows the same operating principles and as such I'll suggest that both MG1 and MG2 can both always operate as motors or generators independently. Clearly the "net" portion of summed power goes to and from the battery while any that's equal between the MGs will move back and forth between them as needed to effect ICE to wheels gearing and start or stop the ICE. Both MGs are effectively positional-controlled servo motors and as such they not only start and stop the ICE but do that with such precision and control of the inertias involved that a "bump" is not felt by the driver when the transitions take place. Since electrical power conversion between MGs will always incur losses, one optimization I've noted on early HSD applications is that at continuous level-road highway speeds the electrical power flow between MGs is intentionally minimal to minimise fuel consumption, meaning MG1 will be nearly stationary at those speeds. The ICE will be providing the base-load power to move the car while primarily MG2 will maintain battery level as a generator when cruising or slowing, and provide motoring power to help with passing as needed. In summation the HSD is simply a brilliant exploitation of electrical power conversion technology, high speed computation, the differential properties of planetary gear sets and the low losses inherent with a simple gear reduction unit at cruising speeds. On another note, there are mechanical details that I find interesting that might also be interesting to other viewers. One is the choice made between ball bearings and tapered roller pairs. I noticed that the intermediate reduction shaft had tapered rollers yet experiences little thrust loading due to the roughly balanced use of helical gears. I wonder why that choice of bearing? The second detail is the use of splines and planetary gear sets. Splines act like a solid shaft when under torsion and as-such one side must be allowed to float ever so slightly to equalise 'tooth' loading. Planetary drives similarly need the planet carrier (or individual planet gears) to float radially very slightly to also balance tooth loading. As such there may be small details present to effect those requirements. A good example was the shaft that passes from the main drive area to the rear wheel clutch. It's long enough to allow the male spline to float. Similar radial clearance requirements may arise between the ICE (journal bearings) and a closely positioned adjacent ball bearing. The journal will always "orbit" a tiny amount in the bearing ('whirling') and allowances need to be made so that it can do this freely. Lastly, the rear drive multiplate clutch. This works just like every other "slip and grip" AWD I'm familiar with - a magnetically-actuated pilot clutch actuates a bi-directional ball ramp mechanism. In order to keep the main clutch compressed there must always be a very slight slip of the pilot clutch, with consequential but very minor heat and wear. Thanks again John!

[@RotoRCol]

wow great knowledge here, just curious what did you study and what are you working on?

[@WeberAuto]

Thank you Paul! Thanks for the great information too!

[@paulaxford6754]

@@RotoRCol I studied mechanical engineering in the late '70s followed by technical field work mostly in UK/EU automaker/aerospace engine/turbine dynamometer test facilities. And I did learn a lot working with some helicopter transmission engineers while we spent a few months commissioning a new test facility for them. And of course decades of home car DIY always helps, especially when you have the background to recognise why things are done the way they are. I'm retired now but I'm currently working on understanding an issue with my EV's gear reducer where the factory internal magnet doesn't seem to capture ferrous particles as it should and leaves the oil highly contaminated with iron and aluminium. Adding a magnetic plug helps but the automaker seems oblivious to this odd defect that is still present in their production 4 years later. Only a tiny number of gearboxes actually fail completely but there's undoubtedly added noise present due to the unnecessary wear on bearing and gears. I certainly get a lot out of John's videos as you can imagine!

[@Sauceyjames]

Not all CVTs are the same. Great to know the eCVT from the Prius is on some of the hybrid Subarus as well. Great for parts sourcing

[@erik_dk842]

I doubt that the parts interchange.

[@Miata822]

What a fascinating transmission. While the electronically variable ratio is the star of the show (I believe the Ford Maverick hybrid is similar), it is the rear drive clutches that really caught me by surprise. Clearly the electromagnetic clutch couldn't carry a meaningful load, but using that clutch to make the ball ramp clamp the 'real' clutch is so mechanically simple that it is genius. The pump drive is also quite clever. That's an expensive transmission but should last almost forever. Even the clutches should see little wear since they won't really see meaningful slip. It looks like they could be replaced without splitting the case. Thank you for another great video!

[@WeberAuto]

Thanks Bill!

[@brianb-p6586]

Ford hybrids have generally used the same power-split hybrid approach as Toyota.

[@20vtrojo]

Very good video and excellently explained

[@markgentry6688]

Great job ! 👍

[@maldo72]

this channel is gold ... top notch explanation been watching you for years ...

[@WeberAuto]

Thank you very much

[@brianb-p6586]

The solenoid and ball ramp rear drive clutch is a very common design. It can be found in the transaxle (as here) or in front of the rear final drive (differential) in various brands of vehicles which use variable clutch actuation to drive the rear axle. So this nice explanation of that clutch system also applies to many other vehicles.

[@Miata822]

It was news to me. Very clever design. I love mechanical simplicity.

[@WeberAuto]

Thank you, yes, I have seen it in AWD truck transfer cases too.

[@brucechan9140]

I wonder why Subaru would not flip their default configuration and makes rear wheel drive by default and use the ball ramp to send torque to the front axle? It would certainly give the car a more dynamic driving experience. It's not like it has some packaging restrictions since pretty much all the hardware is already their in their symmetric AWD layout, except they have to provide a much beefier drive shaft to handle the constant torque to the back, and prob. reinforce the rear suspension a little. But to me, that would be a relatively small design change to be able to place their cars in a completely different market segment.

[@brianb-p6586]

@@brucechan9140 These cars are very front-heavy, so primarily RWD would not be desirable. The rear final drive might need to be stronger, but the drive torque distribution would matter very little to suspension.

[@brucechan9140]

@@brianb-p6586 I agree with you completely on the fact that subaru is inherently front heavy, the engine is actually mounted mostly in front of the front drive shafts. But I dont see why weight distribution has anything to do with driving torque send to the back. Afterall, there are plenty of pickup trucks with empty beds rolling down the roads everyday. And if I am not mistaken, audi's longitudinal quattro layout with torsen center diff is rear biased. I don't see why subaru can't do it.

[@user-dt8be4zq8z]

Your videos are next level to all the other "how does it work" ones!

[@WeberAuto]

Thank you very much!

[@Erelyes]

Great video. Subaru were a bit late to the party with PHEVs, no wonder they borrowed Toyota tech. Maybe Suzuki will be next. I'd be interested in seeing a breakdown of the Mitsubishi PHEV system as fitted to Outlanders as well!

[@ziliboba73]

Thank you for great job!

[@WeberAuto]

Thanks for watching!

[@sauerjoseph]

You are the BEST!

[@joeyfarkas9617]

thank you! phenomenal video. I wanted a rav4 hybrid but now id rather have the mechanical awd!

[@pablopicaro7649]

Cross-trek ECVT is marvelous, RAV4 probably lot easier to find, and more parts will be available in future

[@WeberAuto]

Thank you!

[@brianb-p6586]

The mechanical AWD is fundamentally less capable of suitable control than the electric rear drive. The only advantage is that Toyota only equips the rear drive with sufficient cooling for limited operation, so the power sent to the rear and the time it is used are limited. Both systems must minimize rear drive operation to improve efficiency, so they're both just front wheel drive until needed.

[@petrnemecek4379]

RAV4 has better system than this. It has lower losses in the drive line = better fuel efficiency. Offroad performance should be almost similar.

[@erik_dk842]

An inline Toyota 4 cylinder is much less prone to cylinder head failure than a Subaru boxer engine.

[@mikestone9839]

fascinating and even I could understand it all!

[@nobodynoone2500]

Great stuff as usual! Thank you for all your work, and for sharing it with us!

[@WeberAuto]

My pleasure!

[@user-lh4cq5bk1k]

Hello from Kazakhstan. good job thanks. it seems to me that this system is similar to VGRS

[@iuliangheorghe5160]

Thank you for the effort to bring us the news. Outstanding presentation.

[@toomanyuserids]

John, did your bootcamp back in March. Good to see you doing videos in the new facility now.

[@AdelAlouani]

Very well explained! I have a question regarding CVT operation with MG1: When MG1 is rotating slower than the engine, does it act as a generator with power generated being proportional to this RPM ratio or does it actually require MG1 to act as a motor to force it to rotate at the required RPM to make the appropriate gear ratio? For the last mode explained, where MG1 turns backwards to make the highest overdrive, I understand that it has to add power, so it's acting as a motor, but what about the "in-between" where MG1 is stopped up to the point where it's the same RPM as the engine? Thank you for all the visuals and explanations and examples! It definitely helps a lot.

[@dude-hh9db]

I understand that MG1 is never turning slower than the engine. For 2 reasons: a) the crankshaft shall not rotate backwards and b) the motor rpm is usually too high for the output, in this case MG1 receive power from the combustion engine and transfer it electrically to MG2, which makes the drive system an electric torque converter.

[@petermolnar6017]

Top video! Thank you for all your efforts Professor Kelly!

[@WeberAuto]

Thank you very much!

[@LaneLarson]

Fantastic!