Posted by: mastertech1 | 24/11/2009

How often should I have my cars automatic transmission flush service?

In the last few years this question has come up many times? I say in the last few years because up until around 2004 most vehicle manufacturers not only recommended, but their dealerships strongly urged a transmission flush service every 2 years or 30,000 miles whichever came first. This has become the norm in the automotive service and repair industry. Then along came long-life transmission fluids, actually these have been around for years, and now the dealerships are saying 80,000 or even 100,000 miles in between services. Maybe you have noticed that the 30,000 and 60,000 mile services have gone down considerably in price and services performed since 2004, this is especially true in the Toyota – Lexus, and Honda – Acura line of vehicle.

 The only thing that has really changed is the dealer and manufacturer mind-set. They simply have changed their focus to vehicle sales instead of service and maintenance. Most do not care how long your vehicle lasts, they are expecting even hoping that you will trade it in every few years, thus never suffering the consequences of poor vehicle maintenance. 

Dirty fluid (41k miles) vs. New long life fluid

So what has research in the field shown as to when it is best to perform automatic transmission flush services? Time and again the same answer is held true, the best way to maintain your vehicle’s automatic transmission is to have a competent repair shop fully flush all of the fluid with  a flush machine every 2 years or 30,000 miles whichever comes first. Many of my Lexus customers are very surprised when they come to me for the first time, after having the dealer perform the 30,000 mile service, and I show them what their transmission fluid looks like when you do not do it every 30,000 miles. (See picture of Lexus Long-life fluid after only 41,686 miles, normal driving.)

A typical fluid flush with long life fluid is going to be somewhere in the neighborhood of $160 US. However my experience is that when this type of service is kept up regularly it will save you literally thousands of dollars in the long run, and give your transmission trouble free miles well into the 200,000 maybe even 300,000 miles! A good investment indeed.

For those of you who do not keep your vehicles that long, lack of service may not affect you in the 2-3 years that you drive this vehicle, however it will affect the vehicle and the planet in due time. Benefits to you are; stronger resale value of a well-maintained car or truck, and the “green aspect” of keeping it out of the wrecking yard as it begins to change hands.



  1. I have a Honda Odyssey 2006 with 80,000 miles. Transmission shudder started around 70,000 to 80,000 miles. Honda dealer suggested to service Transmission, which meant drain and refill not flush. In fact he had no means of flushing the transmission.
    Dealer wanted to change the torq converter.

    After reading your article on flushing transmission, I took car to Colman Taylor for transmission flush. They said this would not make problem worse but could advance problem. They added bottle of smart blend addative. This helped but problem is still there between overdrive and next gear. If I accelerate through this range the shudder does not occure. WHAT SHOULD I DO.

    • Hello Darrell, I am sorry to hear that you are having this issue. I tell you… Honda better start paying attention or this is going to have serious repercussions on the long term view of their product.

      As far as what you should do, it is difficult if not impossible for me to diagnose via the net. However I can give you some pointers.
      Keep in mind that this article was written to help prevent this issue, not solve it once it has arisen. What is the current condition of the fluid? If it is not too dirty I recomend a full flush using genuine Honda fluid, if there is any chance of correcting this, this is it. If the fluid is filthy, I do not recommend a flush, as it can make the problem worse. If that does not improve your situation an inspection by a qualified transmission shop is in order. You are not going to want to hear this, but in most cases a complete rebuild is in order to correct this problem.

      All the Best,

  2. I’m at a loss as to how the dealer from which I purchased my 2005 CRV (now with 96m+ miles) has not addressed this problem. Obviously it is not a new one. I also have the “shudder” at about 45 mph and the first thing that the service dept. told me was that the brake rotors probably needed turning. I said it had nothing to do with braking. They then told me maybe I should have my tires (less than 12,000 miles) rebalanced. When I asked them if they would do a complete trans. flush, they said they didn’t have those facilities in their shops.

    My next step is to have them do a trans. fluid change (as small as it is) and see if that has any effect.

    I have also heard that someone ordered a Transmission Control computer download which, in a case of a Honda Pilot seemed to take care of the problem. This all sounds like the old idea of “if I keep changing parts, eventually I may find the solution” and this coming from the mechs and techies who should know by now what is the true solution, bad design or engineering somewhere along the line.

    I know enough to be dangerous! If this is Honda’s approach, my next car will probably be something different.

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