Join Date: Aug 2012
Location: Austin, Texas
Car: 2001 VDC/SC One of a Kind
Feedback Score: 2 reviews
In reply to both previous post, Yes, a flush/fill will help extend the life of the internal components, and No, the transmission is not totally sealed once assembled.
It is assembled in an closed room that is ventilated in such a way that it controls dust intrusion into the clutch packs and bearing surfaces. Once the transmission is assembled, it is not filled while in the room. Really, think about it. In much the same way, your engine was also assembled in an environmentally controlled room, but you change the motor oil regularly. The coolant.
So, flushing the system is not a hazard. I flush mine with a filter replacement every 30k miles. All my Subarus have always gotten the same treatment. My 99 OB went 300k miles without issue with the transmission or the engine. ON the other side of the coin, my VDC, although I have all the records since the first Mobil 1 oil change, never had the transmission serviced in the prior 140k before I bought it and it suffered a broken bearing and ruptured seal which caused a chain reaction to burned clutches. (The seal issue caused the clutch problems. Still unknown exactly what caused the bearing to break. There were pieces of it in the pan.)
As I posted previously, with advances in fluid technology and the CVT transmissions in some models, it is not necessary to flush and fill often. It is up to you, the owner what you want to spend on maintenance. If a CVT is flushed, be sure the proper fluid is used or it will damage the shift solenoids.