CVT Transmissions

Subaru introduced the CVT (Continuously Variable Transmission) Transmission in 2010 with the Legacy/ Outback platform, and by 2015 converted their entire lineup to the CVT transmission. While most vehicle manufacturers have gained a bad reputation with their CVT transmissions including Subaru, Subaru has the best CVT transmission on the market. In 2010 Subaru of America did not have a service interval for the CVT transmission and stated that the fluid was a lifetime fluid. There is no such thing as lifetime fluid, and the lack of service of the transmission led to many CVT transmission failures. Today Subaru of America still does not recommend the CVT transmission fluid be replaced at a certain interval, instead recommend inspecting the fluid every 30,000 miles. While this is acceptable, we do recommend that the CVT transmission fluid be exchanged every 60,000 to 90,000 miles with a drain and fill of the transmission. When the transmission fluid reaches over 100,000 miles it becomes burnt and debris enters the CVT transmission fluid, which clogs the transmission valve body that controls the flow of the transmission fluid. When these valves become clogged it prevents the transmission from functioning as it was intended.

Over the years we have obtained extensive knowledge of Subaru's CVT transmission and have discovered that they are a very reliable transmission if serviced properly. One of the biggest failures we see with the CVT transmission is a failed valve body solenoid, which requires replacement of the transmission valve body and a fluid exchange. When the valve body is addressed, it prevents damage to the transmission and allows the transmission to continue to function as designed. Another big failure of the CVT transmission, although it is not as common, is bearing failure of the front differential. The Subaru CVT transmission combines the front differential into the transmission housing and is lubricated by gear oil and not the CVT transmission fluid. The differential gear oil is often overlooked by many technicians as there is no dipstick to easily check the fluid and is believed to be part of the sealed transmission unit. When these bearings fail the transmission assembly must be completely disassembled to reach the differential bearings. When this occurs, it is best to replace the CVT transmission assembly as it is more costly to rebuild the CVT transmission instead of replacing the unit with a different transmission. We recommend the differential gear oil be serviced every 60,000 miles to prevent this type of failure.