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Discussion Starter #1
Bought my 99 sts with 60,000 miles on it. I have no idea if the trans fluid has ever been serviced. How do I know when it is time to change it?
Is it safe to change it? I have heard that you are not supposed to EVER change trans fluid in some cars. Is this true? Any input will help. Thanks fellas

-mike
 

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94 ETC,97 STS
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I've never heard of a car where you're NOT supposed to change it. I have heard of lifetime fluid where you supposedly don't have too change it. I don't agree with that but that is only a personal opinion.

I feel you will get longer life out of the trans with fluid changes.
 

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Discussion Starter #4
I also feel that it is a good thing to do. I just heard that transmissions get used to the fluid that is there already, and changing it can cause problems.
Ever hear something like that?:confused:
 

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98 Deville, '15 Ford Fusion Hybrid Titanium, '12 Ford Escape
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detroit99sts said:
I also feel that it is a good thing to do. I just heard that transmissions get used to the fluid that is there already, and changing it can cause problems.
Ever hear something like that?:confused:
I've heard of damage being done by "bad flushes". A lot of it read on this board. Most people here recommend doing a dropping of the pan and refilling.

I needed mine done, I'm at 97,000 miles now. I had it done at 95,000. I took it to my dealer that I bought the car from. I asked the guy about the flushes and what he thought about them, and told him about all the information I had read on this forum. He told me that the only time a flush would do the kind of damage that is discussed on here, is when there are already problems with the transmission or little problems exist already.

even if i didn't need to change the fluid (life indicator always read 100%) if anything, it provides me with peace of mind, at a cost of $125. :histeric:
 

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'87 Jeep, '10 Thruxton, '00 Duc 748, '01 748R (853cc)
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The Transmission has a fluid life monitor that will read 100%, unless there a problem with the tranny, that would cause the fluid condition to suffer. If you really want to change it, go ahead but a flush isn't necessary. Just drop the pan, and remove the side cover to get most of the old ATF fluid out, and then refill it. You can also clean the screens if you want, although it's not really needed unless they are dirty, or have particulates in them (in which case, I would think there would already be problem). The problem with some flush machines, is that they cycle the fluid back through the transmission opposite the normal flow direction, which can be detrimental to seal, accutators, and other various components. As the guy you spoke to said, this damage is usually caused by small debris trapped in the fluid. A flush isn't really necessary though, so you might as well just drain it, and refill it.
 

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Please take time to read the posting on the Technical section regarding "never do a flush to a transmission." As danbuc stated, reversing the flow forcefully enhances the possibility of resending debris out of the screens backwards through one-way only valves (wrong way) is not exactly ideal, as per the engineers that designed these valves.

The fact of the matter is that a transmission flush is easier to do than actually dropping the pan and doing it the way it's instructed on the service manual. This is an easy buck for a shop that has a machine already. It's quicker, and there's no need to do anything else--according to them.

Do at your own risk, but as Ranger once said on here--I wouldn't do it on my car.
 

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Detroit99STS,
It is always safe to change it. The manual says it is good for life if not driven under "severe conditions" (towing, hilly, livery service). I do mine at 100K. Others do theirs sooner. There is a trans fluid life indicator but unlike the OLM, it will always read 100% unless you over heat it.

Danbuc,
I assume you meant remove the side cover drain plug as opposed to the side cover.
 

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Discussion Starter #9
Fellas,
thanks for the quick replies and tips. I think I will wait until 100k before the change. Currently at 85k. I am glad I know not to do the flush now.:rolleyes:
 
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