Transmisson flush?

daniel3507 · Dec 22, 2008

Ive been thinking about flushing my transmission fluid in my 93 automatic. ive talked to people though and they said not to flush it because new fluid could damage the transmission. any thoughts?

exbass94 · Dec 22, 2008

Bullcrap. Regularly changing the fluid is the best thing you can do to the transmission, and is the only way to help it last a long time. I flushed mine at 135k miles about 2 years ago and it still works flawlessly. The only maintenance prior to that was a pan drop/refill at about 65k. My dad used to be the one in charge of the car maintenance. Now that I'm in charge, all of our trannys get flushed every 30k.

Psychopete · Dec 22, 2008

A "quick flush" wouldn't hurt (new filter and retop off fluid), though I've heard 50/50 on actual transmission flushes at the dealership. I wouldn't say yes or no, just because I don't have experience with it. I'm just cheap, and have cheap vehicles.

I just "quick flushed" my '93 Tempo before winter.. Fluid was a little dark, but not a lot of material.. The main thing for me is getting the new filter and the crap out from the bottom of the trans pan. I had a TH350 that had a mountain of material that slipped bad when it got colder (bought in summer).. Did help w/ the slipping issue for the time being. Drove it for a year, sold it, and never heard anything about it. I still think I see it driving around. TH350 is cheap enough to replace.. Hell, I just paid $225 for a known good working AOD.

But overall, a quick flush is certainly better than doing nothing at all.

Pete

FordCustom1 · Dec 22, 2008

some people say not to change the fluid because....in badly worn tranny the fluid contains the ground up clutch peices that are allowing you to have friction where needed to motivate....and when the fluid in one of these badly warn trannies is changed the new fluid does not contain this friction.....and causing you to have to rebuild a tranny sooner then if you left the fluid in it....then the people say ohhhh the the new fluid ruined my tranny....

i would agre that changing fluid often is better for your tranny in the long run.....however.....if its not broke i don't fix it....

daniel3507 · Dec 22, 2008

i have 85 thousand on my tranny. all and all it runs pretty smooth. when i run at around 40 though its almost like it hesitates to shift gears but never actually does it till about 45. thats the reason i was thinking about a complete flush but now im not so sure

exbass94 · Dec 22, 2008

85k is nothing. I would flush it without hesitation. Although I doubt it will solve your problem, I would do it anyway as it's just good preventive maintenance. Like I said, changing the fluid is the only way to make that trans last.
If you're really that scared of a flush, then just drop the pan, change the filter, and top it off with some fresh fluid. This will replace only about 1/3 of the fluid in the trans, so it won't be such a "shock" to your trans, but you still get some fresh fluid in it at the same time. Then maybe do a few more pan drop/refills every 10k. By that time, all of the fluid in the trans should be pretty much new. I would then flush every 30k thereafter.

daniel3507 · Dec 22, 2008

thats kinda what i was thinking. and the tranny hasnt been abused or driven hard or anything so thats why i was thinking it wouldnt be a big deal. im wanting to replace my all my fluids and the transmission was the only one i was iffy on

thegoat4 · Dec 22, 2008

Many automatics fail from clutch dust plugging the screen of the suction pipe. That causes the pump to cavitate at high rpms and push metal crap into the guts of everything else. Changing the fluid and filter every so often will prevent that. Plus, the fresh fluid will better lubricate and clean internal parts, keep seals working longer, and reduce operating temp.

The whole "don't change your fluid or the transmission will slip" argument is almost an old wives tale. It kinda-sorta applies when you have a ridiculously neglected transmission that has a hell of a lot of sludge. The new fluid's detergents will break up the sludge and may cause problems, depending on where the chunks go, although the vast majority of these problems turn out to be side-effects of having a plugged filter screen.

So, change your fluid and filter. I personally wouldn't go through the trouble of actually flushing the system out as you can accomplish the same thing over the course of two filter changes which you should be doing anyway.

And the bit about the the fluid in worn trannies having "friction" in it due to clutch dust... No.

Will · Dec 22, 2008

Don't get one done. I think they have a machine that filters the fluid and then pumps it into the next guys car. They don't even change your filter when you have this done.

Change the filter and add whatever fluid is needed to top it off. You can flush it for real yourself. You need a clean bucket of fluid and a bucket to catch old fluid. You basically disconnect your tranny lines and let the old fluid run into the empty bucket while the new fluid is sucked back into the tranny. When you see new stuff coming back into the bucket of old stuff, turn it off, seal it up, restart it and check the fluid. Thats a real flush and the only one I would bother doing.

projectnitemare · Dec 23, 2008

My shop does a real flush except we use an exchange machine to make things a little faster and cleaner. Does the same thing that you would do by disconnecting a line and pouring new in. We don't do just a fluid exchange, the price includes pulling the pan and a new filter. If you aren't changing the filter you are wasting your time. If your trans is already having problems any flush or filter change usually won't correct it anyway and sometimes it will speed up the process of killing a bad trans. For one in good working order new fluid never hurt anything.

Matt

Transmisson flush?

daniel3507

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exbass94

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Psychopete

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FordCustom1

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daniel3507

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exbass94

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daniel3507

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thegoat4

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Will

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projectnitemare

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