[Subabubaru]

But upping the torque could just shift the failure point(s) to the engine or elsewhere in the drivetrain.

Given the build of the Ascent tasks like offroading and pulling are what showing that the Ascent CVT transmission isn't suited for continuous and borderline abuse. Nothing in the driveline or powertrain would wear out prematurely because of torque demand increases. The ECM tuning is really good at controlling destruction of the engine on 87 and that is pretty awesome. Holding torque is the difference between unlocking the torque converter to let the rpms flare to maintain speed vs leaving the torque converter locked up and allowing the engine to make torque.

What?!

No way (said every DSM owner -like myself- ever). I ain't afraid of no /insert issue/. I ai't hearda no supportin' mods. !!! 😅

But like @Subabubaru 's post reads....wouldn't that be fun, though?!

I just think of the longevity of parts and how the Ascent would still maintain it's premium appearance and gain feel by actually having a transmission that shifts. Being able to apply full torque under load at lower rpm would appeal to more people as the CVT feels slushy and lacks refinement when it "flares" to apply enough power to suit the demand. I find disappointment in the fact that my base Impreza with the TR580 feels more refined with it's traditional feelings CVT with linear input demands to output commands.

 

[Jim_in_PA]

Given the build of the Ascent tasks like offroading and pulling are what showing that the Ascent CVT transmission isn't suited for continuous and borderline abuse.

And yet...Robert routinely accomplishes that with his beast of an Ascent.

 

[Robert.Mauro]

Given the build of the Ascent tasks like offroading and pulling are what showing that the Ascent CVT transmission isn't suited for continuous and borderline abuse.

Neither has been a cause of failure, though it's a common misconception that there's a relationship between either of those and failures.

I'll go into more details in my vids. Waiting for some more CVT parts from Subaru for one of the next segments.

 

[AgentK]

And yet...Robert routinely accomplishes that with his beast of an Ascent.

And yet he had his CVT replaced

 

[AgentK]

Neither has been a cause of failure, though it's a common misconception that there's a relationship between either of those and failures.

None of the lighter Subarus are having the same issues at the same scale as the Ascent, the outback with the same TR690 seem to be much more reliable, and as you say everytime a comparison between the Ascent and any other Subaru comes up, the Ascent is much heavier so it is very possible there is a link between the vehicle's weight and Subaru's CVT failure rate. That would mean that towing would also increase the rates of failures as it will need to pull a much heavier weight.

 

[Subabubaru]

Neither has been a cause of failure, though it's a common misconception that there's a relationship between either of those and failures.

I'll go into more details in my vids. Waiting for some more CVT parts from Subaru for one of the next segments.

For my 2021 it didn't fail but it did prompt SOA to replace my CVT at 63k due to flaring, surging and shuttering of the transmission. It still worked before the replacement it didn't work correctly. That is my point. The weight of the vehicle is an increased load on the transmission. Smaller vehicles with this transmission aren't experiencing the undesirable side effects of overuse.

And yet...Robert routinely accomplishes that with his beast of an Ascent.

Yes but that can't be a blanketed statement as it is only anecdotal and isolated at best. Many more people complain of the premature failures of these transmissions along with the bad fuel mileage related to the tuning of these transmissions.

 

[Robert.Mauro]

For my 2021 it didn't fail but it did prompt SOA to replace my CVT at 63k due to flaring, surging and shuttering of the transmission. It still worked before the replacement it didn't work correctly. That is my point. The weight of the vehicle is an increased load on the transmission. Smaller vehicles with this transmission aren't experiencing the undesirable side effects of overuse.

Neither the weight of the vehicle, nor tow load, is responsible for the failures.

Yes but that can't be a blanketed statement as it is only anecdotal and isolated at best. Many more people complain of the premature failures of these transmissions along with the bad fuel mileage related to the tuning of these transmissions

I track more of these than anyone except Subaru.

 

[Robert.Mauro]

And yet he had his CVT replaced

Yes, before my crazy adventures, and due to Competition Subaru giving it to an oil change tech who didn't know how to fill it, which triggered the issues related to WRK-21 that broke my chain guide.

Thanks to me and 22 other owners, you all got the recall. 😉

Remember, I know a LOT more about these things than Internet speculation.

 

[Titanrx8]

Unlocking the torque converter to allow the engine to "flare" (increase RPMs?) will only increase torque if the RPMs are well under 2k because this engine attains peak torque below 2k. Above that rpm the torque curve is a tabletop. HP will increase with RPMs but not torque.

Unlocking the torque converter would only be necessary when the CVT doesn't have a numerically higher ratio to engage.

 

[Robert.Mauro]

Unlocking the torque converter to allow the engine to "flare" (increase RPMs?) will only increase torque if the RPMs are well under 2k because this engine attains peak torque below 2k. Above that rpm the torque curve is a tabletop. HP will increase with RPMs but not torque.

Unlocking the torque converter would only be necessary when the CVT doesn't have a numerically higher ratio to engage.

When I get to the front of the CVT vids, I will go over that, and there's a TON of misinformation out there, but, short version is...

Torque converter is unlocked when CVT is below 160ish. ALL speeds.

Above 160ish degrees:
0-11 mph: Torque converter unlocked

12-19 mph: partial lock approaching full at higher speeds

20+ mph: FULLY locked ALL the time. Ratio is irrelevant. Accelerator position is irrelevant. Engine RPM is irrelevant. It's locked literally ALL the time, contrary to a bunch of misinformation out there.

 

[Robert.Mauro]

Some of the people who saw the vid wanted to know where the planetary gear set went. It slides into the reverse brake (once all of the clutch plates are aligned). That big thing on the outside of the carrier isn't a gear.

 

[TSiWRX]

Some of the people who saw the vid wanted to know where the planetary gear set went.

Meanwhile, my USPS packages have been sent on a whirlwind US-wide trip....both my mom's birthday present for me as well as my new fidget toy have been delayed! So, yes, I would like to know where my planetary gearset happens to be, now, too!

 

[Robert.Mauro]

Here's where the planetary gearset goes... The ridged outside of the carrier slides into the reverse "clutch" (align the clutch plates first).

 

[Robert.Mauro]

None of the lighter Subarus are having the same issues at the same scale as the Ascent, the outback with the same TR690 seem to be much more reliable, and as you say everytime a comparison between the Ascent and any other Subaru comes up, the Ascent is much heavier so it is very possible there is a link between the vehicle's weight and Subaru's CVT failure rate. That would mean that towing would also increase the rates of failures as it will need to pull a much heavier weight.

Pressure regulation is a little different, as is what the TCM does (load vs torque are different). Regardless, they are having some of the same issues the 2021-2022 Ascents had.

2019 through some 2020 Ascents had a harness connector issue. The harness connector was changed since then, and all new CVTs come with the new connector (been revised since, see link below)

I've mentioned a number of times that back in 2021, Subaru, came out with an additional pressure sensor, and have been working on programming changes, to address pressure regulation issues.

LOW speed, load or NO load, has been the issue that causes the later "any speed" slips. If you watch the slip vids, you will see that it's TR690 based Subies (not just the Ascent) just cruising along under no real load. Weight was never the issue (I know what the chain and variators are rated for - we are not remotely close).

Subaru has finally published some of the information in a TSB, and someone shared that...

https://www.subaruoutback.org/threads/model-year-2025-changes-fa24-engine.569406/?post_id=6495894&nested_view=1&sortby=oldest#post-6495894

NOW, I can start talking more about the subject. I have been waiting for Subaru to publish the information. Back in 2022 or 2023, I spent part of the afternoon talking with the engineer who created the new sensor method for these things - now that details are being made public, I can start telling you all everything (that's public or on STIS) about it.

SHORT VERSION:

• No, the Ascent weight has nothing to do with it.
• No, towing has nothing to do with it.
• No, off roading (except "slow speed pressure regulation issues" that happen on and off road) has nothing to do with it.
• No, the LuK chain and variator design isn't remotely near its design limit. LuK "Big Chain" is rated for 442.537 lb-ft of torque. That is not a typo.

 

[TSiWRX]

Oh WOW...this thing is HEAVY.........

The machining really is pretty nice, @Titanrx8 . You'd like it, I bet.

And you were right, @Robert.Mauro . That it's used certainly doesn't seem to have impacted in how smoothly the gears mesh together. It's a fidgeting dream.

Gonna clean up the shipping preservative (I think my buddy's AK was packed in less Cosmoline ) and see if I can't find a place to display this. The wifey doesn't like my taste in "art." 😅

 

[Robert.Mauro]

Oh WOW...this thing is HEAVY.........

The machining really is pretty nice, @Titanrx8 . You'd like it, I bet.

And you were right, @Robert.Mauro . That it's used certainly doesn't seem to have impacted in how smoothly the gears mesh together. It's a fidgeting dream.

Gonna clean up the shipping preservative (I think my buddy's AK was packed in less Cosmoline ) and see if I can't find a place to display this. The wifey doesn't like my taste in "art." 😅

Wait until you all see the rest of the pieces. I have two special packages from SoA being delivered today, so I can show you all the entirety of "chirpy".

The technical review of my details and data was completed a while ago, so, as long as I don't go off script, I'll be done with that video soon.

I have SOOO much more planned for the community, especially since SoA is being very helpful.

 

[Robert.Mauro]

Here's the forward clutch... time to work on the next vid!

Very special thanks to Subaru of America for the shiny parts!!!

If these vids do well, there will be many more, based off questions from all of you!!!

 

[Robert.Mauro]

Here's the "Chirpy" assembled and exposed...