Potential CVT Issue - 2015 3.6R

Hi Guys,

I've owned a 2015 3.6R for close to two years now - it currently has about 68,000 km (42,000 miles).

I have always felt that the CVT was a little jerky at low RPM and realise that this is really just a nuance of they way they behave. Its pretty annoying in stop start traffic, although I can get around it with careful throttle control. I have also never really been a fan of the manual paddle shifts as they seem to cause the car to lurch a bit between shifts - it just doesn't feel right.

Recently, however I feel that the 'jerkiness', for lack of a better word has become worse, not only at low RPMs but also under heavy acceleration. I have noticed that as the car winds out and reaches the simulated shift points it tends to jerk a bit as the CVT changes gear ratios. The feeling is almost like the change in acceleration you feel when using the paddle shifts, but not as strong. I have noticed this during the normal 'I' driving mode and I haven't tested it in the sports modes to see if its there.

I recently drove my mother's 2017 outback (2.5L) with only about 20,000km, and although this is a completely different engine and CVT I was hoping to find that it behaved similarly. This was not the case though - the CVT felt much more refined and smooth, with hardly any hesitation or jerking.

What are your experiences with the 3.6R CVT? Is what I'm experiencing normal behaviour? Perhaps a symptom that arises with more kms? Potentially a software issue that could be flashed out?

Any help/feedback would be great. Thanks!

So far my 2016 3.6R CVT that just passed 40k miles last week has been solid. The good news is that you're well within the extended warranty period of 10yr/100k miles (unless that's just a United States warranty extension?).

If you're pretty convinced there is something not right and it's not in your head, I'd take it to a dealership. Even if they say it's fine and there's nothing for them to do about it, I think it's good to have that documentation for future purposes.

I want to get a CVT fluid drain and fill at about 50k miles, but from the sounds of it, most dealerships don't want to touch it. Something I'll need to do more research on, but maybe if there are signs of issues it'll be something they'd be more willing to try.

Yeah... really not sure if its in my head or not but it definitely drives quite differently from the 2.5L Outback, albeit they are different year models and makes.

Not sure about the CVT extended warranty in Australia as there doesn't seem to be anything published about it online. Have emailed them to ask.

I have also undertaken the CVT reset procedure available online which involved disconnecting the battery, turning the car to the on position and off a couple of times etc. Not really sure this made a difference and if its applicable to non US variants.

Not sure about the CVT extended warranty in Australia as there doesn't seem to be anything published about it online. Have emailed them to ask.

I would advise you to make sure that you make your concerns known to your dealer and have those concerns documented. Hopefully everything will be OK in the future, but if not, you will at least have some "documentary back up" if needed.

I have had no problems with the CVT in my Australian (Japanese made) 3.6R.

When the CVT warranty was extended in USA, I did however contact Subaru Australia just to enquire as to whether they were intending to also extend the CVT warranty. Here is their reply ...

" .... Thank you for contacting Subaru Australia.

Subaru of America is a separate business entity to Subaru of Australia, they also manufacture their own vehicles to different product specifications and design regulations specific to the American market, which would mean many of the internal components within the vehicle will be completely different between country to country, this is why what occurs in the American Market often will not translate to the Australian market.

Please understand that a transmission is made up of many components internally, and there can be a multitude of reasons as to how these components could fail, in the event you should have a concern with your CVT you should raise your concern with a Subaru service centre immediately. However should you have any concerns outside of your warranty period, a claim for 'goodwill' assistance can be submitted through to Subaru Australia, which will be assessed accordingly on a case by case scenario.

Subaru Australia stands behind the terms of our manufacturers warranty and should you require any assistance in the future in regards to your CVT, please do not hesitate to contact us....."

... What are your experiences with the 3.6R CVT? Is what I'm experiencing normal behaviour? Perhaps a symptom that arises with more kms? Potentially a software issue that could be flashed out?

 

Any help/feedback would be great. Thanks!

It might be worth checking your engine oil level. Apparently if the engine oil is overfull it can cause CVT surging. Read page two of the attached two pages from the US June 2014 Subaru TechTIPS (2014.06JunTechTIP-1.pdf) below.

I’ve always read the engine oil level cold on my Subarus on level ground as follows:

With the engine cold (leave overnight) & before starting the engine; remove the dipstick, wipe it clean, leave it out for about 10 minutes, re-insert, take it out & read the lowest side of the dipstick. The oil should be at the full hole, if it is above this it is too full.

Taking the reading with the car on level ground is important, a slight angle can make a difference to the reading. Because the dipstick enters the sump at an angle the oil will be shown lower on one side of the dipstick than the other - so read the lower side, not the higher side.

2014.06JunTechTIPS-1.pdf

Thanks for the feedback guys... I have double checked my oil and its a little under the full mark so I guess its not that - however, some of the symptoms in that tech tip do sound similar to what I believe I am experiencing.

Ok, that rules out too high an engine oil level then. In my experience the 2.5i will feel different to drive compared to the 3.6R, but I haven’t felt either surging. In ‘I’ mode at light throttle the 3.6R will do everything quietly, smoothly & effortlessly.

I have experienced severe surging in my previous SJ Foz XT (same TR690 CVT as the 3.6R) when climbing a steep mountain, which felt like a CVT issue. To fix the problem I ran upper engine cleaner through the engine & cleaned the MAF sensor (I suspected boost clamps but they weren’t the problem).

How is your engine running? If not running properly it can seem like the CVT is at fault. If it was my car I would do the following; run some Subaru SA459 Upper Engine Cleaner through the engine, clean the MAF sensor, & do an ECU reset. (I notice you have done an ECU reset).

The Subaru SA459 Upper Engine Cleaner should have been used at every 6mth/12,500km service. I don’t know how true this is but there was a post on an Australian forum from a Tech at a dealer who said sometimes they don’t use it because it is too much trouble. So even though some owners were being charged for it they weren’t getting the benefit of the cleaner. I found this cleaner definitely works (except on the FA20DIT engine which I won’t go into here).

It is important to follow the directions on the can of SA459. Only half a can should be used before starting the engine to prevent the risk of hydraulic lockup, then the rest of the can used. Not as important on a NA engine like the 3.6R as on a turbo engine, but in addition to spraying this into a vacuum line it can also be sprayed into the throttle body to help keep that clean.

The quickest way to reset the ECU if you don’t have the software is to disconnect the battery.

The method I have always used is as follows:

▪ Before disconnecting the battery, turn OFF the engine, climate control a/c, SatNav/sound system & lights so there is minimum load on the battery.

▪ Disconnect the battery.

▪ Press the brake pedal a few times to remove any residual current from the system.

▪ After at least 30 seconds reconnect the battery (this time can be extended just to make sure any capacitors still holding a charge have discharged).

▪ Wait at least 15 seconds then turn the ignition to ON (two presses of the start/stop push button) but don’t start the engine (keep foot off the brake pedal when pressing the start/stop button so that the engine doesn’t start). (make sure the climate control a/c, SatNav/sound system & lights are still turned OFF).

▪ Wait at least another 15 seconds (during this period you may hear various clicks & other sounds).

▪ Start the engine & let it idle for at least 60 seconds without touching the accelerator or brake (keep the climate control a/c, SatNav/sound system & lights turned OFF during this period).

▪ Take the car for a good drive. The throttle will be unresponsive for a while & fuel economy will be poor for the first approximately 3/4 tank of fuel.

Due to disconnecting the battery, the SatNav loses some user configured settings (red light & speed camera settings etc) which are reset to the default settings – so these will have to be reconfigured again.

The driver's side window loses the auto down function after disconnecting the battery, so follow the following initialisation procedure:

▪ Close the driver's door.

▪ Turn the ignition switch to the ON position.

▪ Open the driver's side window halfway by pushing down the power window switch.

▪ Pull up the power window switch & close the window completely - continue pulling up the switch for approximately 1 second after the window has closed completely.

▪ Push down the power window switch until it clicks to open the window completely.

There is an extended ECU reset procedure that was given to ‘tigger73’ by Matt (thottlehappy). Matt tunes vehicle for a living & also posted the method I use on an Australian Forester forum.

This is tiger73’s topic that explains that procedure.

I use CRC MAF Sensor Cleaner which is a bit pricey but it lasts a long time (don’t touch the sensor with your fingers). You could leave this & try the Upper Engine Cleaner & ECU reset first to see if that works before trying the MAF sensor cleaner.

If you do any of the above please let us know how it goes.

Cheers for the detailed help... Overall the CVT drives relatively smooth once acceleration is steady, but at low speeds its a bit jerky - also sometimes breaks the car during deceleration, especially up hill. and then seems to let go as it decides that it wanted to change gear ratios. It just doesn't feel right at times and that is what's been giving me suspicions about it.

I did my own servicing about 4 months ago which comprised an oil/filter change as well as front and rear diff service. Although the fluids where not Subaru they were high end and met all the specs required as per the manual.

I have been worrying myself that the diff servicing may have been somewhat related to this but I believe that its highly unlikely. I used Castrol Edge 5W-30 engine oil and Castrol Sytrax Universal Plus 75W-90 for the front and rear diff. Drained and topped up the diff fluids until overflowing out of the fill plug on a level surface so don't see any reasons for this to be the issue.

What I did however neglect to do was the upper engine cleaning procedure. I was not aware that this was required until a friend mentioned it to me shortly after but thought I may be able to get away with it until the next service. The car does seem to idle a little roughly, although its barely noticeable and I really only notice is as a slight feeling sitting at traffic lights - no real noticeable change in rpm or anything.

I will take your suggestion on performing the cleaning and see how it goes. I think the upper engine cleaner will require an engine oil change though no?

... Overall the CVT drives relatively smooth once acceleration is steady, but at low speeds its a bit jerky - also sometimes breaks the car during deceleration, especially up hill. and then seems to let go as it decides that it wanted to change gear ratios. It just doesn't feel right at times and that is what's been giving me suspicions about it. ...

I’m guessing you meant braking downhill, not uphill. If so, my previous 2016 Liberty 3.6R & current 2019 Outback 3.6R did/does that when using Adaptive Cruise Control. At times it seems like the engine braking & CVT ratio change is too aggressive so it backs off then re-applies engine braking/CVT ratio change again. (it uses CVT ratio change & engine braking initially to reduce the speed back to the set speed before applying the brakes if they are required).

Coming back from the shops today I drove with a very light throttle at a constant slow speed (about 40 to 50km/h) to see if I could detect any jerking, & at times I could just detect very slight surging. After having three CVT Subarus since 2013, it is something that I have become used to & now don’t notice.

I remember raising this same slight surging issue with a Tech who used to service my vehicles when I owned an SH Forester XTP (which didn’t have a CVT). When driving the same way as above, this vehicle used to slightly surge exactly the same. I was told that this model does this at almost closed throttle slow speed running & Subaru Australia was aware of it. I don’t think a software pak file was ever released to address this. I just got used to it.

Something else you may experience: Going back through my records I came across an issue I raised with the same Tech when I owned a 2016 Liberty 3.6R. In ‘S# auto & manual’ (& to a lesser degree ‘S’ mode) at around 50km/h when quickly applying partial throttle from closed throttle the vehicle starts to accelerate instantly briefly, then hesitates briefly, then accelerates normally - like a flat spot. I was told this is how the 2016 Liberty 3.6R is. He told me a software pak file was released for the earlier gen6 Liberty 3.6R which was worse, but it didn’t completely fix it & needs another one. I don’t think another one was ever released, but I haven’t checked my current 2019 Outback 3.6R to see if it has been improved.

Castrol Edge 5W-30 A3/B4 engine oil and Castrol Syntrax Universal Plus 75W-90 are fine. I’ve been using those for quite a while. The dealer that services my vehicle uses Castrol Edge Professional A3 5W-30 engine oil (recommended by Subaru Australia) & Castrol Syntrax Universal Plus 75W-90. According to a Castrol Technical Advisor I spoke to quite some time ago, Castrol Edge Professional A3 5W-30 & Castrol Edge 5W-30 A3/B4 are almost identical.

For the front diff the oil should be filled untill it flows out of the overflow drain plug hole, not the charge pipe filler hole, is that what you meant?

It would be advisable to change the engine oil after applying the upper engine cleaner, although I was told by one Tech that it was ok to apply the cleaner after an oil change.

The issue I was describing happened today as I was reaching the top of a hill with traffic lights. I braked a little as I got to the top of the hill - when I let the brakes to come to a stop that's where I noticed the strange surging issues. I would expect the car to come to a slop with smooth deceleration but it felt like the CVT was grabbing a bit (slowing the car down too fast) before letting go. It definitely felt different to when the car puts the brakes on during adaptive cruise - really hard to describe it to be honest.

Its quite possible that I may have convinced myself there is an issue when there isn't but I'll do the upper engine clean and see how I go - might drop by the dealer at the end of the week before work goes back and see if they can give it a quick test drive and/or give me a spin in another 3.6R to see if the issue is also there (although it'd be a newer model).

One other thing I have noticed is that if I start the car and immediately put it in drive (sometimes I forget to wait a second) it clunks into gear quite loudly and jerks the car a bit, even with the brake applied. I notice that if I wait a few seconds before doing it it goes into gear much more smoothly.

Drained and topped up the [front & rear] diff fluids until overflowing out of the fill plug on a level surface so don't see any reasons for this to be the issue.

That's correct fill procedure for the rear differential, but not for the front. If you did that in front, the front differential is now grossly overfilled, and it could be causing some of the "surging" you feel.

Its quite possible that I may have convinced myself there is an issue when there isn't ...

Without me driving the car it is a bit hard to say. My previous post was a bit rushed (I was getting the windup from my better half), but I was trying to explain that these cars are factory tuned to run reliably lean so as to get the best fuel economy & to comply with pollution requirements. Running lean can cause very slight surging. If the engine isn’t running right it can be worse.

The issue I was describing happened today as I was reaching the top of a hill with traffic lights. I braked a little as I got to the top of the hill - when I let the brakes to come to a stop that's where I noticed the strange surging issues. I would expect the car to come to a slop with smooth deceleration but it felt like the CVT was grabbing a bit (slowing the car down too fast) before letting go. It definitely felt different to when the car puts the brakes on during adaptive cruise - really hard to describe it to be honest.

That doesn’t seem right. I can’t remember our Liberty or Outback ever doing that. It’s possible that you do have a CVT problem. Do you know if your Liberty had done any hard work like towing before you bought it?

One other thing I have noticed is that if I start the car and immediately put it in drive (sometimes I forget to wait a second) it clunks into gear quite loudly and jerks the car a bit, even with the brake applied. I notice that if I wait a few seconds before doing it it goes into gear much more smoothly.

I always wait a couple of seconds before engaging drive or reverse, so I just started the Outback from cold & moved straight to drive to see what happens. I got a very slight jerk which I wouldn’t have normally noticed, but definitely no clunking. By waiting a couple of seconds before selecting drive I didn’t get any jerking, just a very smooth engagement, which is also what the Liberty did from memory.

The only time I’ve heard a clunking is when I wash & hose the car in the afternoon then immediately park it in the garage overnight in park & with the handbrake on. If I start the car the next morning I sometimes get a loud clunk when I engage reverse, release the handbrake & apply throttle, which I think is the handbrake releasing. It only does this after washing the car. The Liberty also did this.

For the front diff the oil should be filled until it flows out of the overflow drain plug hole, not the charge pipe filler hole, is that what you meant?

That bit is important as ammcinnis also noted. Did you notice if the surging issues got worse after doing your last maintenance?

See attachment: 3 Differential Gear Oil.pdf

What I did however neglect to do was the upper engine cleaning procedure.

What TF is this? Never heard of it in three years owning my car, haven't seen it in the manual's service schedule, the dealer hasn't pestered me calling it a "recommended maintenance".

What TF is this? Never heard of it in three years owning my car, haven't seen it in the manual's service schedule, the dealer hasn't pestered me calling it a "recommended maintenance".

Hi Shooter, just to let you and ammcinnis know that here in Australia in the Japanese made Legacy's (Liberty here) "Upper Engine Cleaner (part #SA459) is in our factory supplied Maintenance Schedule ( I am looking at it as I type this) and is "performed" at every scheduled service. Just as an added note, Fuel Additive (part #SA718) is also "performed" at every scheduled service as well.

Hi Shooter, just to let you and ammcinnis know that here in Australia in the Japanese made Legacy's (Liberty here) "Upper Engine Cleaner (part #SA459) is in our factory supplied Maintenance Schedule ( I am looking at it as I type this) and is "performed" at every scheduled service. Just as an added note, Fuel Additive (part #SA718) is also "performed" at every scheduled service as well.

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That's correct fill procedure for the rear differential, but not for the front. If you did that in front, the front differential is now grossly overfilled, and it could be causing some of the "surging" you feel.

Yeah I filled the front diff to the top of the level plug at the time so shouldn't be any issues there. Used the factory manuals to do the work - torque to spec etc.

Hi Shooter, just to let you and ammcinnis know that here in Australia in the Japanese made Legacy's (Liberty here) "Upper Engine Cleaner (part #SA459) is in our factory supplied Maintenance Schedule ( I am looking at it as I type this) and is "performed" at every scheduled service. Just as an added note, Fuel Additive (part #SA718) is also "performed" at every scheduled service as well.

got a picture of that stuff?

got a picture of that stuff?

What stuff do you mean?

What stuff do you mean?

I've got a few photos of the SA459 & SA718 with instructions for the SA459 I can post if you don't have any.

Photos of the SA459 Upper Engine Cleaner (the first two) & SA718 Fuel Additive (the next two) attached below.

Note: These aren’t applicable for the diesel engine.

In case the directions on the SA459 photo can’t be read, the following are the directions for use as written on the can (which is really a two person job):

Should be used every 12,500km/6 month service. Suitable for use in vehicles with a catalytic converter.

• Shake can before use.
  
• Warm the engine to normal operating temperature.
  
• With ignition turned OFF remove convenient vacuum hose from intake manifold and spray approximately half the can into the manifold using the nozzle tube supplied with this can.
  
• Allow the engine to stand for 5 minutes.
  
• Start the engine and run fast enough to prevent stalling while spraying the remainder of the can into the manifold.
  
• Stop the engine as the can empties and allow to stand for 5 to 10 minutes.
  
• Restart engine and rev engine to purge any remaining foam.
  
• Reinstall the vacuum hose.
  
• Road test the vehicle to insure good performance.
  
• Extremely dirty systems may require a re-application.

A lot of rubbish will come out of the exhaust when using this & during the road test. For the above road test after using this I use WOT up to just under the red line in a suitable gear a few times after the engine warms up.

We found the SA459 Upper Engine Cleaner wasn’t quite potent enough to keep the FA20DIT engine in the SJ Forester XT running smoothly. An Australian SJ Forester XT owner found a more potent product (Liqui Moly Petrol Engine Intake Decarb 2733) that worked well on the FA20DIT engines, but quite a few precautions were required when using this (it is very potent stuff).

The full bottle of SA718 Fuel Additive is just added to a full tank of fuel.

I've got a few photos of the SA459 & SA718 with instructions for the SA459 I can post if you don't have any.

Thanks ... I kinda guessed that's what the poster meant, but then I also thought perhaps he meant a picture of the actual maintenance manual.

The issue I was describing happened today as I was reaching the top of a hill with traffic lights. I braked a little as I got to the top of the hill - when I let the brakes to come to a stop that's where I noticed the strange surging issues. I would expect the car to come to a slop with smooth deceleration but it felt like the CVT was grabbing a bit (slowing the car down too fast) before letting go. It definitely felt different to when the car puts the brakes on during adaptive cruise - really hard to describe it to be honest.

 

Its quite possible that I may have convinced myself there is an issue when there isn't but I'll do the upper engine clean and see how I go - might drop by the dealer at the end of the week before work goes back and see if they can give it a quick test drive and/or give me a spin in another 3.6R to see if the issue is also there (although it'd be a newer model).

 

One other thing I have noticed is that if I start the car and immediately put it in drive (sometimes I forget to wait a second) it clunks into gear quite loudly and jerks the car a bit, even with the brake applied. I notice that if I wait a few seconds before doing it it goes into gear much more smoothly.

This is exactly how my 2015 acts. Has always done it since I got it with 17000 miles. Now I’m at 114000. I tend to use manual mode because it eliminates the problem completely. It is very annoying especially in stopped traffic. On flat ground from a stop it gets to like 5mph or so and then jerks. Like you also said. Going uphill in traffic it will very aggressively decelerate at low speeds. Car basically nose dives and shudders. I was thinking to do the front and rear diff fluid this weekend to help with the issue but obviously it’s not going to help. Where did you get the service manual for it? I’ve read that the drain and fill plugs can be confusing and you could inadvertently drain your cvt fluid. I’d like a manual to show me exactly what I should be removing. My 4th gen is so much easier than these cvts.

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