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Can a Trans Flush ruin your transmission?

Old 02-10-2012, 05:21 PM
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V6Frank
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Question Can a Trans Flush ruin your transmission?

So I went to the ford dealership today to get info on a transmission flush, but when i spoke to the serviceman about the job he told me that since my car had 100k, and had never had one done before that he recommends not to do it. He told me that he has seen on frequent occasion that this ruins the transmission and would make the gears lag and/or skip. I thought this was weird but I did not want to automatically discredit him seeing as he works at the dealership. So I just wanted to get some feedback from you guys on this subject, and if this where true, what can I do about my trans?
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Old 02-10-2012, 06:34 PM
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Syracuse315
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Auto I'm assuming?
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Old 02-10-2012, 06:44 PM
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Nuke
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I've heard some similar stories with the basis being that the pressure of the flush will dislodge crud that has accumulated over that 100k miles and will get into the valving and hose things up. I can't say that I'm convinced but I've heard that enough to make me wonder.

BTW, I've had about 8 vehicles with auto trannys that never had tranny service done that had over 150k-200k on them when I got rid of them.
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Old 02-11-2012, 12:32 AM
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V6Frank
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Yea its pretty interesting, I have been asking around and apparently it isnt as uncommon as I had originally thought. but now I wonder because I do want to service the tranny, before it starts building more miles, but not at the expensive of it getting worse. I feel as though if ive put myself in a loose, loose situation. Lol

Oh and @Sryacuse315 correct it is an Auto, I kinda forgot to mention lol
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Old 02-11-2012, 06:32 AM
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Nuke
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I'd probably ask a few tranny specialists just to get a better handle on it.
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Old 02-11-2012, 06:48 AM
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X6StringerX
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Rather than flushing the transmission, I would recommend dropping the pan, changing the filter, and topping it off with fresh fluid. You won't be replacing all of the fluid because the torque converter will have some in it, but you'll get the majority of it. You'll also have the opportunity to check the pan for any debri, so it will serve as a status report on your transmission. If you drop the pan and it's full of crap, you may want to start making plans to buy a replacement. If you drop the pan and everything is nice and clean, then you'll have piece of mind.

I was a shop manager for a couple of years and we didn't even own a flush machine. We always recommendeded a pan drop and filter replacement for the same reason the guy at the dealership told you not to flush yours. Flushing can, indeed, loosen crud. Replacing the fluid can as well, but to a lesser degree.

Let me ask you this, would you change your engine oil but leave your old filter in place? If the answer is no, then you know what to do.
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Old 02-13-2012, 09:47 PM
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amustangrocks
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i pretty much agree with x6 sort of. i had mine flushed at 50k and the fluid was black as coal, not a trace of red. i had it flushed again at 85k, still dirty but not as bad. the filter in the trans is just a metal screen, so its nothing like a oil filter and thus doesnt do much good to replace it before 100k so i opted for the 13 qt flushes. thats why the filter is not called for in the service schedule. they do recommend the fluid be changed around 35k for adverse conditions like towing (i would include racing) ect. i`m at 100k now so this next time though, i`m gonna drop the pan, replace the filter, and just replace the 5 qts and start doing 5 qt drains and fills more frequently( dont need to waste the money on filters that often). i think a filter and 5 qts is your best bet starting service at 100k

life of the trans is mostly dependent on heat. thats the reason for deeper pans or extra trans coolers. as the fluid gets broken down, it looses its cooling qualities and the trans suffers. its a crap shoot either way. i still think maintaining it like you would your engine from the start is the best thing. ive seen guys on here that waited till high mileage, got flushes, and the trans went out. so pan, filters, 5 qts or run it till its toast, its your call.

Last edited by amustangrocks; 02-13-2012 at 10:20 PM.
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Old 02-20-2012, 09:16 PM
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zanypunk
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Originally Posted by amustangrocks
i pretty much agree with x6 sort of. i had mine flushed at 50k and the fluid was black as coal, not a trace of red. i had it flushed again at 85k, still dirty but not as bad. the filter in the trans is just a metal screen, so its nothing like a oil filter and thus doesnt do much good to replace it before 100k so i opted for the 13 qt flushes. thats why the filter is not called for in the service schedule. they do recommend the fluid be changed around 35k for adverse conditions like towing (i would include racing) ect. i`m at 100k now so this next time though, i`m gonna drop the pan, replace the filter, and just replace the 5 qts and start doing 5 qt drains and fills more frequently( dont need to waste the money on filters that often). i think a filter and 5 qts is your best bet starting service at 100k

life of the trans is mostly dependent on heat. thats the reason for deeper pans or extra trans coolers. as the fluid gets broken down, it looses its cooling qualities and the trans suffers. its a crap shoot either way. i still think maintaining it like you would your engine from the start is the best thing. ive seen guys on here that waited till high mileage, got flushes, and the trans went out. so pan, filters, 5 qts or run it till its toast, its your call.
Doing flushes after 100k is not recommended at all. It all depends on the luck of the customer :P To those that have auto trans and do burnouts. Your trans fluid is already black so do yourself a favor and buy yourself a stick-shift if you're into doing burnouts. Note: The Snow does kill your auto trans :P
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Old 02-21-2012, 10:14 AM
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tx_zstang
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+1 on just dropping the pan and changing the fluid/filter. DEFINITELY get that done!

Most subsequent problems also occur when fluid level is not filled back up properly.
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Old 02-23-2012, 01:22 AM
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Thanks for all the great info guys, its really appreciated. At this point im glad the service guy gave me the heads up. Lucky me huh lol
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