Homemade transmission flushing machine

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I've been reading about transmission flushing machines and it looks like all they do is equal the pressure they inject new oil into the system to the pressure the transmission pump pumps the old oil out. I had an idea to build something similar more simply. It may not work, but I just exhibit here to know your opinion. Imagine a big syringe with the capacity of your transmission, that is the same in both sides, needle side. Then you don't have the common syringe piston, just the rubber part, but with a metalic core just like a Tea-Pot, running all along the syringe so the rubber piston doesn't twist. Then you move the rubber piston to one extreme and fill it with new oil. Connect the outlet side of the cooler line to the empty side and the inlet to the full side. Your start the engine and the oil starts to flow, pushing the piston and pressuring the new oil into the transmission with the same pressure as it leaves, so the oil level remains constant. You just have to be very careful to stop the engine before the piston comes to the end, so you don't put too much pressure into the lines. What do you think?, would it work?. Do you know if this already exists or if there is something similar that could be adapted to do the job? Another posibility would be to use a veeery long transparent hose that you would fill with new oil, then just connect both lines to it and wait till the new oil is into the transmission and the old is in the hose.
 
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you could use a fairly fat hose, so you wouldn't need as much length. fold it back and forth. it would have to have enough capacity. that method, i could see.
 
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Sounds like a decent idea actually, although it would be cheaper, easier and safer to just perform a cooler line flush and replace all the fluid. If your transmission fluid wasn't changed regularly, or is a high mileage unit, a flushing machine can also do more harm than good.
 

ecco123

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 Originally Posted By: Captain_Klink
you could use a fairly fat hose, so you wouldn't need as much length. fold it back and forth. it would have to have enough capacity. that method, i could see.
I also thought about it, but with the small cooler hose connected to a big hose I think maybe the transmission pump wouldn't provide enough flow and the oils could end up mixing. You could also leave a meter or so of air between the old and new oil so the new oil is pushed by the air.
 

ecco123

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 Originally Posted By: Falcon_LS
Sounds like a decent idea actually, although it would be cheaper, easier and safer to just perform a cooler line flush and replace all the fluid. If your transmission fluid wasn't changed regularly, or is a high mileage unit, a flushing machine can also do more harm than good.
My fluid is only 3000 miles old and my transmission was rebuilt two years ago. I just want to change because it overheated because of a failure in the radiator. Anyway, I can't see any differences between a cooler line flush and a flushing machine apart than the flushing machine is faster doing it. What are the other differences?
 
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I thought about making my own by taking (2) 2.5 gallon water jugs. Filling one with ATF and leaving one empty. Disconnecting the tranny lines from the radiator.. hooking hoses to the lines and putting them in the appropriate jugs. Simple!
 
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If you use the hose method, you could add the equivalent of a oil pipeline pig. In other words, you could separate the two liquids (old and new) with an object that was the size of the inner diameter of the hose - marble, golf ball, ect. If you use the syringe method, you could put in a pressure relief bypass that would let the new fluid flow around the old fluid once the end of the plunger displacement had been reached. You could even add two three way stopcocks separated by a valve and you would never have to detach the lines. Just hook-up to the stopcocks, turn the three handles and let if flow.
 
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The end result as you have contemplated is the same between a flush machine and a clear 3/8 hose, flushing two quarts at a time. The flush machine is cool in that you pour in the fluid and you can walk away, do whatever and it will finish the job for you. I keep looking for a T-tech on ebay, like I really need a $4000 flush machine!
 

PT1

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I was thinking about using a feed tank for the new fluid and hanging it higher than the trans so gravity feeds the inlet hose. But the more I think about it simply pumping 2 quarts at a time was so easy why use anything but my existing funnel/hose setup. It only took 10 minutes to actually do the flushing with a helper to turn the car on and off. The time consuming part was taking on and off all the plastic splash panels.
 
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I just put my hose coming from the cooler line into the open top of my fluid vac because it is clear and marked for quart volume. I just poor it in as fast as it comes out. If I get behind I stop the car and fill till get caught back up. This is so easy and done so rarely I can't imagine taking the time to build a contraption to replicate the function of a flush machine. Not to mention it is just more hoses and connections that might leak and cause a mess. I make enough messes as it is so I'm sticking to the simplest method.
 

ecco123

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Sorry for bringing this back after so long, but I still didn't do the oil change and it's time to do it now. When you say you use a funnel to pour the new oil in as the old one goes out through the cooler outline, do you mean into the dipstick hole or into the cooler inline that goes back to the transmission? (in my case the radiator top nipple). Does the transmission oil pump make a vacuum effect in that line?. I can't see the oil going back through all the circuit from the radiator without that help. I don't like the dipstick method much as I belive you can't completely remove all the old oil with that method.
 

PT1

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If you have a dipstick you fill through the dipstick tube. If you have a sealed trans you use the fill hole and a funnel. The cooler line is for old fluid exit only. The pump will not produce vaccum and draw new fluid into the system. I use the return line that exits the radiator trans oil cooler so the cooler gets flushed as well.
 
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First most flush machines us a cancainer with a bladder in it. The line going out of the trans goe to the side of the conatiner that the bladder rests one. The other side of the bladder is where the new fluid is. As the fluid pumps out of the trans it puts pressure on the bladder forcing the new fluid in the return line for the transmission. Simple hydralics in action. The syring idea would not work well. It would work about as well as sticking a hose down the transmissions fill tube and sucking the sump dry. Your method and the tube down the fill up tube both fail to get what is int he circuits of the trans and the converter. It the transmission must be running to get the torq conveter and the rest of the fluid inside the trans that is not in the pan! By car that have drain plugs on their automatics like all Toyota's and you wil never have that issue. Drain and refilling what comes out of the sump every 15K miles is too idiot proof to change to any other means. Like wise you could simply put a tube down the filler tub to the bottom of the pan and suck out the fluid. ATF is thin especialy afte it has been warmed up. THey make little pumps that hook to the car battery that will do the job just fine!
 

ecco123

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Originally Posted By: PT1
If you have a dipstick you fill through the dipstick tube. If you have a sealed trans you use the fill hole and a funnel. The cooler line is for old fluid exit only. The pump will not produce vaccum and draw new fluid into the system. I use the return line that exits the radiator trans oil cooler so the cooler gets flushed as well.
Thank you PT1. Ok, so if I disconnected the line that exits the radiator, as you do, just the oil that goes from there to the transmission would keep the old oil, is that correct?. Almost 100% of the oil flushed with that method, isn't it? How much oil do you let going out each time before stopping the engine and refilling through the dipstick? And, lastly, would you also remove the drain plug to clean the magnet, even if you were flushing al the oil with this method?
 
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ecco123

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Originally Posted By: JohnBrowning
First most flush machines us a cancainer with a bladder in it. The line going out of the trans goe to the side of the conatiner that the bladder rests one. The other side of the bladder is where the new fluid is. As the fluid pumps out of the trans it puts pressure on the bladder forcing the new fluid in the return line for the transmission. Simple hydralics in action. The syring idea would not work well. It would work about as well as sticking a hose down the transmissions fill tube and sucking the sump dry. Your method and the tube down the fill up tube both fail to get what is int he circuits of the trans and the converter. It the transmission must be running to get the torq conveter and the rest of the fluid inside the trans that is not in the pan! By car that have drain plugs on their automatics like all Toyota's and you wil never have that issue. Drain and refilling what comes out of the sump every 15K miles is too idiot proof to change to any other means. Like wise you could simply put a tube down the filler tub to the bottom of the pan and suck out the fluid. ATF is thin especialy afte it has been warmed up. THey make little pumps that hook to the car battery that will do the job just fine!
Thank you John. That container and bladder system sounds really good and simple. I wonder how those machines are that expensive. Isn't there a cheap version for non-professionals? I know using the drain plug would be the simplest option, but I've read that you only change about 2/5 of the total amount of ATF, so it keeps mixing with the old ATF. Doesn't sound like an optimum option, but maybe the positive effects on the transmission are huge after a few changes, I couldn't tell. About your idea of sucking the ATF with a pump, it sounds good, but I'm sorry but I haven't understood. (I'm not very good understanding mechanics, plus english is not my main language, sorry blush What is the filler tub? If I take a look at my transmission there are only three places you suck ATF from: the drain plug, the "hot line" that drives the oil to the radiator in the front, and the "cool line" that brings the cooled ATF. Are any of those three the "filler tub"?
 
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Originally Posted By: WishIhadatruck
I just put my hose coming from the cooler line into the open top of my fluid vac because it is clear and marked for quart volume. I just poor it in as fast as it comes out. If I get behind I stop the car and fill till get caught back up. This is so easy and done so rarely I can't imagine taking the time to build a contraption to replicate the function of a flush machine. Not to mention it is just more hoses and connections that might leak and cause a mess. I make enough messes as it is so I'm sticking to the simplest method.
+1 thumbsup
 
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We service a ton of vehicles like this: locate the output line from the trans, disconnect it wherever is easiest. Sometimes it comes off the trans easier than the radiator. I made a little adapter set from Home depot brass stuff, fits almost any domestic car. Just put an appropriate length of hose on it and get a bucket. Then you run the car. The fluid will come out of the trans into my measured container. The SECOND you see any bubbles/foam/interrupted flow, etc. shut her down and refill. Repeat. This doesn't hurt anything and works well. But you still need to drop the pan and change filters, clean magnets, etc.
 

ecco123

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Originally Posted By: SteveSRT8
We service a ton of vehicles like this: locate the output line from the trans, disconnect it wherever is easiest. Sometimes it comes off the trans easier than the radiator. I made a little adapter set from Home depot brass stuff, fits almost any domestic car. Just put an appropriate length of hose on it and get a bucket. Then you run the car. The fluid will come out of the trans into my measured container. The SECOND you see any bubbles/foam/interrupted flow, etc. shut her down and refill. Repeat. This doesn't hurt anything and works well. But you still need to drop the pan and change filters, clean magnets, etc.
When you do that, you refill trought the dipstick, don't you?. Also, you drop the pan and replace filter and clean magnets first, then put the pan back, refill and then do the bucket and refill thing, don't you? I've read that, in old cars like mine (1991 Toyota Land Cruiser), the ATF filter is just a metal grill, instead of the more complex filters they use now, and you don't need to change it every oil change. Does that sound right? I say that because my filter is only 10.000 miles old (pictures here: http://www.bobistheoilguy.com/forums/ubb...629#Post1559629) I just want to replace the oil because it reached high temps and doesn't look as good as it should, so it may be enough to replace the oil and clean the magnet in the drain plug. I don't feel able to remove the pan and install it back with a new gasket by myself.
 
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PT1

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Originally Posted By: JohnBrowning
First most flush machines us a cancainer with a bladder in it. The line going out of the trans goe to the side of the conatiner that the bladder rests one. The other side of the bladder is where the new fluid is. As the fluid pumps out of the trans it puts pressure on the bladder forcing the new fluid in the return line for the transmission. Simple hydralics in action.
Hmm...similar to having 4 or 5 beers while watching the Brown's game..... Coffee2
 
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There seems to be some confusion here. Some are saying to use the OUTPUT line of the tranny. Others are referring to the RETURN line to the tranny. I was always taught to use the return line as the drain and pour the new fluid in the dipstick tube.
 
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