Safe to flush overdue transmission?

[avh]

Hello! I have a 2015 Subaru Outback that is ~113,000 miles. I purchased from a family member several years ago. They said the transmission has never been flushed to their knowledge, and I haven’t kept up with the service schedule very well. I’ve heard that if you flush a transmission that’s overdue, it cause dislodge debris and mess up the car. I called our local Subaru Continental and they said to look at the manual and that they couldn’t give me an opinion. Any thoughts? Thank you!

 

[Dick Foster]

Better late than never.

 

[GuyS1]

I’ve been told by a mechanic that “flushing” can do more harm than good. It dislodges debris that normally is deposited where it doesn’t do any harm and circulates it to all of the fine parts and orifices. Just changing the fluid and filter is better.

 

[keith3267]

Never "flush" a transmission. Just do a drain and fill or a fluid exchange. Your dealer has the correct equipment and the correct fluid. Use of any other ATF other than the type for your transmission will damage it. If an independent mechanic uses a fluid exchange machine, likely they service all kinds of vehicles so their machine will contaminate your transmission. For other services, independent mechanics are just fine, but not this.

BTW, if you have not used the vehicle for towing more than once a year, or towing beyond its capacity for long distance, then you are NOT overdue for a transmission service. It is a lifetime ATF. But if you are concerned, then certainly get the service done, a good nights sleep has value too.

 

[willz]

I agree , just change atf and filter , not to flush . it's better to mix in some new oil , .. if do nothing , you may need to replace cvt . .. indie shop is way less $ just make sure it's the right oil .., dealer is $$ .

 

[Matt42]

Full drain, including the torque converter, and refill.