Skip to Content

7 Unexpected Transmission Problems Of The Subaru Forester

7 Unexpected Transmission Problems Of The Subaru Forester

Subaru never paid much attention to automotive trends, and that is especially true with the Forester. Symmetrical Full-Time AWD and boxer engines are two reasons you should consider the Forester. In this article, however, we are looking at the transmission problems of the Forester. Here is a quick recap:

CVT transmission in the latest, 5th generation Forester is significantly improved compared to the previous generation Lineartronic CVT which was plagued by slipping, hesitation, valve body solenoid failure, stuttering, and even premature failure. Standard automatic transmissions in the 3rd generation Forester are much more reliable than CVTs.

Stay tuned for the whole story if you are not easily satisfied with quick recaps. We are examining all the transmissions of the last two generations and have researched all potential recalls, owners’ complaints, and technical service bulletins. Keep reading!

Common Subaru Forester Transmission Problems

To clarify things, we will separate this section into different model year generations and transmissions that came with a particular generation of the Forester. We are then going to list the specific problems of each transmission. If you want to read about more general problems of the Subaru Forester, click that link!

Fifth Generation – SK (2019-Present)

The latest fifth iteration of the Forester (SK chassis) covered its first real-world miles with the 2019 model year. It features a single transmission option:

  • TR580 Lineartronic CVT

Subaru started implementing the CVT automatic transmission a few years later compared to its competitors. To enhance the durability of its CVT design, Lineartronic uses a chain instead of a standard CVT belt. Let’s see if it worked.

Subaru TR580 Lineartronic CVT Problems

We’ve started our research by focusing on what the owners say. While it is true that there are not a lot of NHTSA owners’ complaints in connection to this transmission, there are 10-15 complaints describing serious issues we can’t look past.

There are two types of complaints that prevail:

1. Rollaway hazard

Several owners report a rollaway hazard with the fifth-generation Forester. An owner of a 2019 Forester best describes the issue:

The contact stated that the vehicle was in the park position in a parking space but was unsure if the shifter was in park when without warning, the vehicle rolled down a hill and crashed into a chain link fence and burial wall.

NHTSA ID Number: 11480941

Unfortunately, we have not seen any recalls, technical service bulletins, or other comments from Subaru regarding this issue. These cases seem to be isolated to a small number.

2. Erratic behavior

Several owners report sudden jerking, hesitation, or acceleration at high speeds and before stopping. As of now, it is not clear what causes such behavior.

An owner of a 2019 Forester reports:

…While driving around 30mph the car will sometimes hesitate and then lurch if the gas pedal is very lightly pressed. sometimes it will do it at higher speeds as well, around 50mph but not typically at freeway speed

NHTSA ID Number: 11253275

There are currently no recalls for this transmission; however, there are several relevant technical service bulletins (TSBs) we do need to mention.

Subaru’s TSB number 16-132-20R provides technicians with a guide for diagnosing reports of CVT chain slipping. Several owners complained about hearing abnormal sounds or feeling unusual vibrations while driving.

These symptoms were quickly connected to the CVT transmission, hence the release of this TSB. The TSB contains a long repair flow chart that sheds information on what could be causing these symptoms. Based on this TSB, cars with diagnosed CVT chain slipping did receive a new CVT assembly and a new transmission control unit (TCM).

Released in October 2021, the TSB number 16-103-16R was released due to a small number of reports regarding the CVT fluid seepage seen on the transmission housing. This TSB shined the light on the origin of these leaks, which is at the sealant used on the CVT’s oil pump chain cover and the input shaft oil seal. 

The TSB instructs the technicians to ensure a faster repair process.

Transmission oil is supposed to be completely clean. If not, any contaminants left behind in the oil cooler will cause premature transmission failure. TSB number 16-42-90R provides the service procedure for correctly flushing the transmission oil cooler. Failing to do so can lead to overheating and premature failure.

The last TSB we want to mention is the 16-102-16R. This quality-oriented bulletin provides the transmission specialist with a new flow chart and additional diagnostic tools to

assist Technicians with troubleshooting diagnostic trouble code P0841- secondary oil pressure sensor performance.

This TSB applies to the 2014-2022 model year Foresters and significantly improved the process behind the diagnosis of the mentioned trouble code. This trouble code can indicate significant damage, which requires a replacement transmission assembly, or a less significant problem that requires a new control valve or pressure sensor.

There are additional TSBs that are a significant help to service technicians but are not something that you or an owner can learn from. One thing must be said: Subaru is fast at addressing common problems and stands behind its products.

Fourth Generation – SJ (2013-2018)

Fourth-generation Forester saw the introduction of the Lineartronic CVT transmission. However, it was not the only transmission Subaru offered in this generation forester. I featured the following two transmissions:

  • 6-speed manual
  • TR580 Lineartronic CVT

Subaru used the CVT option on all variants of the Forester, even on the high-torque turbocharged models. Many automotive enthusiasts will cringe at the high torque plus CVT combination, but if anyone can pull it off, it is Subaru. Let’s see if they did.

TR580 Lineartronic CVT Transmission Problems

As you might have noticed, we always start our research by observing what the owners tell us. A quick scroll through the power train problems of this Forester generation quickly reveals a grim truth behind the Lineartronic CVT.

There are more NHTSA complaints than one can read in under an hour, but we have extracted the most common symptoms and problems reported. Owners of the fourth-generation Forester complain about the following issues:

  • Slipping or presumed slipping of the CVT chain belt
  • Hesitation when trying to speed up
  • Valve body solenoid failure
  • Premature complete failure of the transmission
  • Stuttering of the transmission
  • Unexpected lurching forward
  • Whining noises that signal transmission damage

These transmissions suffer from a plethora of issues. But perhaps, the most disappointing of all is Subaru’s response to these complaints. 

They have released just two technical service bulletins regarding the CVT. The first one, number WTJ-70R, is a service program bulletin addressing certain 2017 model-year vehicles which left the factory with insufficient transmission fluid. Driving with a low level of CVT fluid could lead to transmission failure.

The second TSB, number 16-131-20, provided an update to CVT trouble codes diagnostics which, in theory, did help with CVT problem-solving. However, it did very little to help the disappointed Forester owners who wished there were no problems, to begin with.

As the pressure built up, we would guess that the owners forced Subaru to take more significant action. By releasing the service bulletin number 16-115-18, Subaru extended the CVT warranty of the 2016-2017 model year Foresters from the original five years or 60,000 miles to 10 years and 100,000 miles (whichever occurs first).

It is unclear why Subaru only chose those model years as they were not the only ones affected. However, it was still a welcome move back then, but it means very little for the buyers in the used Subaru market today.

6-Speed Manual Transmission

The 6-speed manual transmission is the way to go if you are after reliability. After reading 300+ powertrain NHTSA complaints, we have only observed two complaints regarding this manual transmission. There are also no recalls or TSBs regarding this transmission.

The two complaints we found are reporting premature flywheel and clutch failure. Both of these components are highly sensitive to how a person operates a vehicle, so the failure might also be isolated cases of failure or a consequence of poor clutch handling habits.

Third Generation – SH (2008-2013)

Third-generation Forester came before Subaru switched to the “Lineartronic CVT” transmission era. The SH chassis, as it is called, offered the following transmissions:

  • 5-speed manual
  • 6-speed manual (diesel)
  • 4-speed automatic
  • 5-speed automatic (S-edition)

And right off the bat, we can say that you should be a bit less worried about transmissions if you are in the market for a 3rd gen Forester. Here is why!

4-Speed And 5-Speed Automatic

Right from the beginning, we were surprised by the low number of NHTSA owners’ complaints regarding these two transmissions, and this is both rare and always a good sign in terms of reliability.

The first problem we have to mention is the rusting of the transmission oil cooling pipes. An owner of a 2010 Forester best describes the velocity of the problem:

Transmission oil cooling piping rusted through causing significant loss of transmission fluid within minutes resulting in a tow to the service garage. This is a known issue to Subaru as they issued a technical service bulletin – sb-10056871-1025 – on sept. 2, 2014 (#16-92-14).

NHTSA ID Number: 11130754

This is the most common problem reported regarding these two automatic transmissions, and while it was a significant problem back in 2009, it is hardly a problem today. If you happen to be in the market for 3rd gen Forester today, make sure these cooling lines were replaced and are in good condition.

Another problem reported in the first two model years of this generation Forester is sudden acceleration. However, we suspect this problem is not connected to the transmission as much as it is to the engine control unit. We base this on the fact that the same reports are also present for the manual transmission version of the Forester.

If you are in the market for a 3rd generation Forester, ensure the automatic transmission has been regularly serviced. Other than that, this unit is reliable and should last a long time.

5-Speed And 6-Speed Manual Transmission

There is not much to say when it comes to the manual transmission. Apart from a few reports of premature clutch and flywheel failures, we don’t think these transmissions have significant problems. 

Isolated reports of premature failures are not out of the ordinary; however, there are no recalls, TSBs, or other major complaints about these two manual units. 

Other Problems Related To The Powertrain

When dealing with an AWD vehicle, ensure there are no weird noises or vibrations coming from the drive axle and AWD components. Subaru’s AWD system is one of the best, but that does not mean it is bulletproof. 

Presuming you are in the market for a second-hand Forester, we would ensure that the vehicle was not often abused in extreme off-road scenarios. We also recommend getting the vehicle’s drive shaft, differential, and other AWD components inspected by a reliable mechanic.

An additional inspection might cost you a few dollars up-front, but it can save you both time and thousands of dollars down the road.

How Long Does A Subaru Forester Transmission Last?

The TR580 Lineartronic in the latest, 5th generation Forester is, without a doubt, the most reliable CVT unit in Subaru’s lineup. Despite the issues we mentioned, Subaru successfully remedied all the problems with TSBs.

Subaru’s efforts establish trust and give us confidence that this generation Lineartronic CVT should last at least 200,000 – 250,000 miles.

The CVT in the 4th generation Forester experienced a bit more issues in the earlier model years. Seeing how it was the first iteration of the CVT, that is to be expected. Nonetheless, there were more and more severe problems, leading to several cases of premature failure.

For this reason, we would expect a slightly shorter lifespan of 100,000 – 150,000 miles.

Third-generation Foresters come with regular hydraulic automatic transmissions, which should last 200,000 – 300,000 miles with regular maintenance. The same goes for all iterations of manual transmissions.

How Much Does A Subaru Forester Transmission Cost?

  • Complete pre-owned TR580 CVT transmission, 5th and 4th generation: 1600$ – 2400$ (eBay)
  • Refurbished valve body for the TR580 CVT: 230$ – 300$ (eBay)
  • TR580 Lineartronic CVT pulley assembly: 450$ (eBay)
  • New CVT units from Subaru: 3000$ – 6000$ (varies by compensation and model)

Have More Questions? Join Our Facebook Group!

Do you have any more questions that weren´t answered in this blog post? Join our free Facebook group and ask your question there. We promise you you´ll get an answer from one of our team members. Join the group here!