View Full Version : Auto Transmission Flush

01-26-2010, 04:57 PM
I've read lots of debates and opinions on flushing of automatic transmissions and the general consensus from what I see is that flushing should not be done, especially on higher mileage trannys due to the potential for seal damage, possible forcing of tranny fluid into the crankcase and other nasty things. However, the local Subaru dealer tells me they flush the transmissions and there is no filter to change.

My question is what would be the difference between your run of the mill quick change place flushing the tranny and the dealer flushing it? I know the quick change joints charge around $90 in my area and the dealer charges $200. Both use the term 'flush' and unless the dealer does something extra or better they probably use similar equipment and procedures for the job.

02-18-2010, 01:36 AM
Yeah I would imagine they're all going to do the same thing - except the non-dealer will bring a filter along with him, then realise he doesn't need it.

Let us know if you find out anything more - would be helpful.

02-28-2010, 10:24 PM
It's a lot easier and less harmful to do a "drain and fill". Drain the auto tranny (~ 4 qts) as only the main transmission (not the torque converter) will drain. Then refill with fresh tranny fluid. Let ait idle about 5 minutes before you drive, and shift gears a few times. Then drive for 500 miles and repeat for a total of three times. By the third "drain and fill" you will have flushed about 97% of the fluid and replaced with fresh fluid.

03-01-2010, 07:34 AM
Well, I ended up letting them do their version of flush for one reason. Every now and again this thing would shudder a little between the 3-4 shift. Would happen both on upshift and downshift. Service manager got it to do it once on a downshift after several miles of driving it. I had reported it twice before and they couldn't duplicate it. He said he felt a flush might clear it up. I'm a bit skeptical, but it hasn't done the shudder thing since. In the interest of avoiding a warranty debate and the fact it's cold as hell and my pit is outside I let them do their thing so they would have it on record that it was done.