Subaru vehicles are generally very reliable and are known to last over 200,000 with just regular maintenance. In a few cases, Subaru owners may notice automatic transmission problems that need to be repaired by an auto mechanic. In this article, we go over those common problems and causes known to affect Subaru transmissions.
Slipping or shuddering on take-off
Subaru cars that use a conventional 4-speed automatic transmission, designated as 4EAT, suffer from one very common issue. It will show up through several symptoms, ranging from slipping, shaking, or shuddering when accelerating from a standstill.
In some cases, there might also be a noticeable slippage in higher gears. Generally, there will be no warning lights or symptoms other than the check engine light.
Possible causes and solutions
- Transmission stuck in 4-wheel drive mode in situations it should be in two-wheel mode. Testing this by installing a fuse into the front-wheel-drive switch under the hood is easy. If this does not eliminate the problem, the cause might be input sensors or TCU itself.
- Faulty or sticking Torque Converter Clutch solenoids, causing slipping or shudder at higher speeds. These solenoids are sensitive to temperature and work fine until they warm up. Although Subaru does not sell solenoids separately, there are aftermarket solenoids available.
Transmission temperature warning
Subaru cars with a conventional 4EAT 4-speed automatic transmission can sometimes suffer from what appears to be an overheating transmission. In most cases, the ‘transmission temperature’ warning light will start flashing. This can happen while driving or even after the car is started.
Possible causes and solutions
- Clogged oil coolers or connecting hoses prevent the circulation and cooling of transmission fluid. The easiest way to check this is to see if the transmission fluid is inside the return line.
- Faulty pressure control solenoid, resulting in loss of transmission fluid pressure. As a result, the flow through the oil cooler will be too slow and overheating. In addition, this can also cause shift issues such as harsh or delayed gear changes.
Stalling when coming to a stop
Newer Subarus with a Continuously Variable Transmission called Lineartronic can have a problem that leads to engine stalling when coming to a stop. In most cases, this will only happen when there is sharp braking after a long drive. After stalling, the car will start and run without any problems.
Possible causes and solutions
- Faulty torque converter, with clutch staying engaged when it should disengage. The resulting lockup causes the engine to stall. The cause of this problem is a worn thrust washer inside the converter that blocks the clutch release. Replacing it with a Torrington bearing solves the issue.
- Incorrect transmission fluid. Make sure that only Subaru’s approved CVT fluid is used.
Growling noise during acceleration
Newer Subarus that have a Continuously Variable Transmission called Lineartronic can develop an issue that shows up as intermittent or constant growling noise coming from the transmission. Usually, this happens only during accelerations, with no other symptoms or warning lights present.
Possible causes and solutions:
- Failure of primary or secondary pulley bearing is a fairly common issue that affects all versions of Lineartronic transmissions. To track down the source of the problem, drive the vehicle at the speed where the noise is the loudest and then shift into a lower ratio. If the noise changes its tone and pitch, the fault is with the primary pulley bearing. The secondary pulley bearing is a probable fault if there is no change. Although Subaru does not sell these bearings separately, aftermarket kits are available.
Engine speed variations
Newer Subarus that use Lineartronic (CVT) transmission have one very common issue, manifesting as variations in engine RPMs when traveling at highway speeds. When this happens, the engine speed will jump up and down without input from the driver. This issue affects both TR690 and TR580 transmissions and will trigger a check engine light, so a corresponding code will be stored.
Possible causes and solutions:
- Faulty TCC solenoid, which cuts off when the transmission reaches running temperatures. Testing involves checking the resistance, which should be 12 ohms at ambient temperature and at around 200° F. If the solenoid is bad, the circuit will be open when it warms up. Subaru doesn’t sell solenoids as spare parts, but there are aftermarket ones. However, replacing them involves soldering.
- Damaged connectors or wiring between the solenoid and TCU.
Based on our experience and research, you are more likely to experience transmission problems if you own a Subaru with a CVT transmission than a four or five-speed automatic transmission. While these are some of the most common Subaru automatic transmission problems, it does not mean that all Subaru vehicles will suffer transmission problems.
We hope you find the Most Common Subaru Transmission Problems guide helpful. Check these troubleshooting and repair guides for more help on your Subaru.