AT fluid change when going FI?
 

I recently went FI. I love it. However I do worry about the longevity of the automatic transmission (currently at 26k miles on the car). Which brings me to my question....

Just how important is a fluid change? I keep hearing/seeing people say "get a quality synthetic fluid!" "Buy this brand or that brand!". Where's the proof though? I'm not going to buy an expensive fluid just because the internet "thinks" it's going to make my transmission handle power better. These recommendations remind of those who think if you aren't running say, fancy Amsoil oil, you are handing your car a death sentence.

What kind of fluid is the stock fluid? Is it not a synthetic?

I don't track my car, and am not doing back to back to back pulls and driving like a maniac on the street. I'm not overly concerned with heat buildup.

However, if running a different type of ATF, or changing it more often, will help my clutch packs in my auto last longer, then I am certainly open to that. I just want more evidence than Joe's buddy who has a friend that is a certified tech that says you have to do this or that, etc.

Thanks for any advice.

Well, I don't have an AT nor is my car boosted.

However, if I did, and the maintenance schedule called for a change at 60,000 miles, I would be tempted to change the fluid every 40,000 miles.

No, I have no data ...... just a gut feeling ......:)


humfrz

The number 1 killer of automatic transmissions (and fluid) is heat, not power. The best thing you can do to extend the life of an Automatic is keep the fluid temperature down. My car is a manual, so I can't speak on the temperatures that the auto transmissions run at, but I suspect they run on the warm side. If the aftermarket synthetics can withstand a higher temperature without starting to break down, then that alone makes them a better fluid and worth switching to. If my car was an auto though, the first thing I would do in the interest of longevity is add an auxiliary cooler.

You'll be fine as long as you keep to the mantaince schedule.
Us manual folk have the extra option to play around with fancy oils. You could put in fancy atf but then again.....it's an auto.

If you're FI there are two coolers you should get regardless an oil cooler and for the auto an ATF cooler. The stock atf cooler uses coolant and is therefore also an atf warmer it transfer heat from the coolant to the atf and at higher temps does a cooling effect. The aftermarket stuff directly cools the ATF fluid itself with it's own radiator and in stark performances case it's own thermostatic fan, when you get the cooler installed your ATF fluid will be flushed and replaced anyway and should last much longer.

Thanks for the replies guys.

I'll just plan on changing fluids a little early. I don't drive hard enough to need a transmission cooler at this point. I'll definitely get one should I start to track it or drive more aggressively on the street.

Still doing research on the topic though.

Honestly from what i've gathered on the forums the autos seem to be bulletproof compared to the manuals

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I would just change it earlier which is what I plan on doing. Ive been FI for 10k miles (I'm at 28.5k now) and I plan on changing it around 35-40k.