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Transmission fluid flush vs drain and replace fluid

edited January 2012 in Repair and Maintenance
I have been negligent regarding the timeliness of replacing my transmission fluid on my 2007 Honda CRV. Have 70K miles without changing and was told by dealership that it should be drained and refilled because it was no longer pink-ish in color and was brown. I asked about flushing and they said something about the pressure may damage the "celenoids?" and cause the transmission to not shift smoothly. I asked 2 different mechanics at local gas stations and they each said to flush it (although one said that if the fluid was black he wouldn't advise flushing and just replace, and the other said that if over 100K, that flushing could cause the transmission not to shift smoothly).

The dealership wanted 120 to drain and replace, the gas station mechanics want approx 240 to flush.

I would like to perform one or the other and am seeking advice as to which.

Thanks.
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Comments

  • I think that your manual suggests a fluid change at 100k miles, so while it would have been nice to change it earlier, you have not been negligent.

    If your fluid is badly discolored at 70k miles, I fear that you have a problem, so it may not much matter whether you drain or flush. Do one or the other and cross your fingers.

    Remember that draining the fluid gets only about half of the fluid out, so you will be mixing fresh fluid about 50/50 with old brown fluid. For that reason, I would tend to want to flush it. However, this is not the first time I have heard that Honda does not recommend flushing their transmissions, so I guess it is best to believe them. It should be pretty easy to drain and replace your fluid. There is even a video doing it on a CRV on uTube. However, if your fluid is discolored, you may want to clean the screen and the pan, and that will be a lot messier. Honda also insists that you use their fluid, but a Google search should identify the manufacturer of their transmission fluid so you can probably get it cheaper elsewhere.

    Some folks say that putting fresh fluid in an old transmission causes it to fail. That is like observing someone die after taking aspirin to ease the pain from a brain tumor and concluding that the aspirin killed them.
  • edited January 2012
    I'm guessing your manual says just to drain and replace it, possibly three times. If so, that's what I'd do.

    As Manolito says, you may be heading for trouble in any event, so keep your fingers crossed.
  • There must be 50 threads about this exact question. Right under the Ask a Question button is a search box.
  • My 2005 Accord owner's manual says to drain, not flush, the fluid. The pressure fro the flush pump may be high enough to damage the solenoids. Get the engine (transmission, actually) well warmed up and then drain the fluid on a flat surface. You will get at least 70% of the fluid out. Replace the fluid and you are good to go. If you are concerned about the remaining fluid, perform another drain and fill cycle immediately. IIRC, the Honda recommendation is to drain and refill twice (3 fills total) to remove essentially all the old fluid. You can do this easily yourself and don't need special tools. You will need a narrow ended funnel to fit into the transmission dip stick tube. That is where the fluid is added. The fluid will cost about $24 for 4 quarts.
  • I work at a Honda store and the 30k by the book is a full fluid/filter exchange. Oil, trans fluid, brake fliud, per steering, and coolent all get changed out for fresh.
  • Your dealer is right, although $120 seems high for something that is basically cheaper to do than an oil change. There is no pan to drop or filter to change on a Honda transmission. The gas station that told you it was black should be avoided completely.

    Honda does recommend their own fluid, and they have come out with a new synthetic fluid, DW-1. You might find something that is equivalent somewhere else, but it will be just as expensive.
  • > I work at a Honda store and the 30k by the book is a full fluid/filter exchange.
    > Oil, trans fluid, brake fliud, per steering, and coolent all get changed out for fresh.

    gsragtop:
    When you make reference to "by the book", are you referring to the maintenance schedule published by Honda motor corporation? Or are you referring to maintenance schedules often published by dealerships?
  • It looks like you have an automatic transmission.

    First you need to make sure you follow the manufacturer's recommendation as a start.

    I strongly recommend replacing the fluid at least every 30 or 40,000, even if the manufacturer list something longer.

    Do not every wait until there is evidence of a problem. Transmissions like to hide their needs until it is too late. It is like going to the doctor. You want to see your doctor once or twice a year, just to make sure.

    Doing so has saved my life. That little spot that did not look right, sent me to the doctor. The next day I was on the operating table with the possibility of waking up with only one leg. Getting to the doctor early saved my leg (over 40 years now) That transmission is the guy who put off seeing his doctor, or did not want to pay for the office call.
  • raj Duct Tape Specialist
    edited January 2012
    Drain and replace with a Honda transmission. Retail for DW-1 is $7ish/qt (use this ONLY). The best method for full replacement is drain/refill/drive until lockup in transmission twice. The final time simply refill.

    My Acura take 3qts/fill not sure what a CRV does(likely similar).

    Never flush a honda transmission.

    The service monitor in my Acura came on at 70k for transmission so previous owner changed it. The 30k recommendation is prudent but may not be what Honda actually recommended if you have the service monitor in yours. Eg the Service A or B or C followed by 123456
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