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About a year ago...

I bought a used 2006 Hyundai Elantra with an automatic transmission and about 70k miles on it.

Before buying it, I had it checked out by a mechanic who said it looked good. They mentioned that the transmission fluid was fine and looked like it had been changed fairly recently.

After buying it, I took it to my trusted mechanic for other maintenance. He looked the car over and also said it seemed in good shape.

The Carfax shows regular maintenance records from before I bought it.

Recently...

I checked the transmission fluid and saw that it was brown.

This was also pointed out to me when I got my oil changed recently. The guy (just an oil change guy, not my trusted mechanic) tried to urge me to get it flushed.

Observations:

  • It doesn't smell burnt to me, although it doesn't smell quite as sweet as I remember it when I first got the car.

    • n.b. I've never smelled really badly burnt fluid so I'm not sure if I'm missing something, but a lot of sources seem to say "you will notice a burnt smell".
  • It doesn't feel sludgy

  • I don't see or feel any small particles in it.
  • It's not black.
  • I haven't noticed any big problems driving it. No clunks or grinding noises.

The owner's manual says:

"As driving distance increases, the fluid color turns darkish red gradually. It is a normal condition and you should not judge the need to replace based upon the changing color."

The fluid is not listed to be replaced until 105k miles (or every 30k miles under "extreme conditions", which seems like a large difference!).

My thoughts:

My thinking is that if the fluid was nearly new when I got it, it should be okay now unless there's some transmission problem that neither mechanic noticed, but that is so extreme as to cause it to get toasted after driving only about 7000 miles.

I've also heard that, if the transmission is indeed going bad, changing the fluid can push it over the edge.

Questions:

  1. Does it make sense to replace the fluid solely based on the color, even though the manual says not to?
  2. Was the guy who told me to change it just trying to make a buck off me?
  3. Should I leave it alone?
  • My thinking is its probably good. It wouldn't hurt anything to change it, though. More than likely it's good until you hit the 105k number. Check it every once in a while to see how it's doing. If it were burnt, you'd know it. The smell is very definite when burnt. – Pᴀᴜʟsᴛᴇʀ2 Oct 30 '16 at 22:55
  • Apparently the fluid can "lose its brown color" over time so it may not be a death sentence: community.cartalk.com/t/brown-transmission-fluid/71099/5 – rogerdpack Mar 21 '18 at 0:09
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Generally speaking, there is no harm in changing an automotive fluid. In fact, new fluid usually performs better than old fluid, whatever the purpose of the fluid. New fluid is clean, has the proper composition, has suffered less oxidation and less heat stress.

Don't believe all the stories about "I changed my fluid and it broke my car." If a component of your vehicle really and truly breaks BECAUSE of the fluid change, it was going to break on it's own with the old fluid sooner rather than later anyways.

If you really are interested in horror stories about fluid changes breaking cars, just a few months ago I changed the motor oil on my '96 Chrysler. Everything went smoothly and I was just finishing filling the engine with the new oil when I reached for the dipstick to check the oil level: the dipstick handle broke right off, and the rest of the dipstick was too far into the dipstick tube to reach with any pliers I had. I grabbed a drill and a long screw and tried drilling the screw into the rest of the plastic handle of the dipstick in order to have something to pull it out with. All that accomplished was jam the rest of the dipstick further into the dipstick tube.

Quick research has revealed that you can remove the dipstick tube, it's just one bolt and then you pull the dipstick tube right out. I removed said bolt and pulled at the dipstick tube: it was seized into place. I tried wiggling it, I tried prying at it, I tried twisting it, I tried everything, the only thing that happened was that the dipstick tube broke off at the base, right where it enters the engine. A few strategic phone calls later revealed that the dipstick tube has been discontinued, there are no replacements available. I went to the local junkyard, and all the dipstick tubes were breaking off at the base during removal. All I wanted to do is change the friggin engine oil, now I have a car that can't move because there's an open hole at the bottom of the engine.

I called a friend over, he brought some leftover copper pipe of a suitable diameter, we removed the oil pan, drilled the rest of that dipstick tube out, squeezed that copper tube in, zip-tied it to something nearby and voilà, I have a brand spanking new oil dipstick tube.

  • 2
    We should have a wiki question / answer that collects horror stories like these where someone wants to do something really simple and it turns into a nightmare project. – Robert S. Barnes Oct 31 '16 at 8:19
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    Changing the fluid( drain and refill) is different from a flush(using a flush machine connected to the transmission oil lines). All the horror stories are after doing a flush. I'm yet to hear a horror story after a drain and refill. – rana Oct 31 '16 at 15:59
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Changing the fluid will not "take it over the edge".

Indeed it's often the first thing to do if the auto has a problem.

Having said that, I wouldn't change it just because of the colour

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I would change it. Make sure and check with the dealership and ONLY use whats recommended for your vehicle. Drain the transmission fluid into a pan and THEN transfer the fluid you drained into some type of a container that you have the capacity to measure HOW MUCH fluid there is. This is important, overfilling or underfilling will Cause you problems Example-you're able to measure that you drained out 3 quarts, put 3 new quarts in the system and you're good to go. There will be some fluid still left in the torque converter but it won't cause any problems

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The 30k mile interval assumes that you are driving on Earth.

Every service interval I have ever seen, from any manufacturer, you end up having to follow the Heavy/Severe/Taxi/Tow/Plow/Duty listed, unless you're driving your vehicle in a bubble.

If you read into them carefully they list things that are completely unavoidable in normal life, and therefore in reality you should always follow the interval that is most often.

The reality is that changing fluids on regular intervals is going to be preferred over deferring the changes.

I hope this helps.

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