Flushing tranny myself

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Listen to unDummy, I can assure you that his method is correct, as I have done a similar thing. I flushed my transmission two weekends ago, here's how:

1. Remove the cooler line and pump out 3.5-4 quarts (or when you see air bubbles).
2. Remove the pan and service it (filter, magnet, gasket, etc.).
3. Re-install the pan.
4. Add 6 quarts of ATF.
5. Pump out 1 gallon of ATF (I used an old FP60 bottle with markings at every 1/2 quart).
6. Add 4 quarts of ATF.
7. Using math, calculate how much you have flushed, and how much should be left in the pan v.s. how much you need in the pan for "Full."
8. Repeat steps 5 and 6 until you use almost (2 quarts less than) total amount of ATF that your system calls for.
9. Top off with enough to bring your level into 1/2 quart below the total full.
10. Check the fluid when hot and add as necessary.

It is safe, you will not cause any harm. Even if the transmission were to run "low" it would only be that way for a matter of seconds.
 
I've helped someone flush their transmission, someone has to aim the cooler line at the bucket while the other person pours it in. We ran one extra quart of fluid though. When all the new fluid was in we were pretty sure it had all be exchanged for new.
 
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One method worth consideration for many is to drain what you can (or suck it out) and refill. Do this every 15-30k. We use this in fleet service and have stopped flushing except when problems are encountered with a given transmission. With over 10 years and a lot of vehicles we can not tell, looking at the data, the difference between the drain and refill (15-30k) method vs. complete flushing (usually 60k).





I also do this on my 91 K1500 and the tranny still pull 6-7K on a regular basis. I have always run Amsoil ATF up until now (260K miles) and drain/fill every 50K.
 
Every other OCI I swap a gallon of ATF in our Windstar (I believe the total capacity is around three gallons, and reccomended interval is 21-30k). I use the cooler-line method..start the car and let the tranny pump a gallon of fluid out. It works great; just starts to foam when it has a gallon pumped out.
 
It seems to me that you need to have a fluid source up high above the hood line and that will gravity feed into the return line and the out line will dump into a bucket below the hood line. You need like a 5gal bucket as the source. run the car until the source bucket gets low and the dump bucket is near full. Required: 2 5gal buckets, plenty of ATF and the hoses to connect to the in/out lines of the tranny. Is that too simple to work??
 
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I have read (myth?) that on a few particular models, the position of the transmission shifter is important when using the cooler line method, i.e., park, drive, or neutral.


I had both a Jeep Grand Cherokee (01) and an 03 Dakota, both with 42RE chrysler trans and they did not pump in PARK. Manual even said to leave in neutral to check fluid level. Have an 06 Dakota now with 42RLE w/ some kind of variable pressure thingie and it can be checked in park.

However , I think there are more chrysler trans than just the 42re that would not pump in park. just FYI.

Can anyone elaborate?

Thanks




Allegedly, some cooler flows are blocked in PARK. I've never encountered it ..but a trans rebuild guy once remarked about a mid 90's Ford OD trans having this feature/characteristic.

..but as SteveS says, you'll find out. If PARK doesn't do it ..NEUTRAL should.


 
Boy the board software munged that reply. Here is what was meant to be read:


I had both a Jeep Grand Cherokee (01) and an 03 Dakota, both with 42RE chrysler trans and they did not pump in PARK. Manual even said to leave in neutral to check fluid level. Have an 06 Dakota now with 42RLE w/ some kind of variable pressure thingie and it can be checked in park.

However , I think there are more chrysler trans than just the 42re that would not pump in park. just FYI.
 
good luck with that jeep tranny. i had an 02 GC and it was pure ----. sold it to get my tacoma and all is well so far lol.. btw it had 96k miles on it when i get rid of it and the tranny was going quick.
 
What is that Dakota doing with a 42RE???? I had a 45RFE trans in mine and loved it. It was easy to drop the pan and change the filter's since it had two.Mine had the standard felt type you normaly see and it also had a thread in oil can type much like a regular oil filter. The main difference being that it was like an aircraft filter screwed intothe transmission as opposed to threading on to a pipe.The second filter was ont he return side from the cooler. If you put the truck on a set of Rhino Ramp's you can easily get 8 quart's out of it!
 
last time i checked, my 545rfe (same as the 45rfe) flows fluid through trans then converter then cooler and then back to the pan. so if the pan is full of clean fluid and adding fluid goes to the pan... where is there mixing of old and new fluid?? does the dipstick not go into the pan but some other part of the trans?

and chrysler is known for having to put the trans into gear or neutral to get pressure. thats why 10 seconds or so in neutral in the morning goes a long way to keeping the initial "morning sickness" to a minimum.
 
Don't ignore all the lubrication, cooling, VB circuits throughout the transmission, and any ATF working points. ATF flow is NOT a perfect loop.

The mixing of old and new is in the pan, throughout the transmission, and in the TC, constantly.

Take a glass(your ATF pan) filled to the brim with milk. And, slowly pour three equivalent glasses of water into the milk(collect the overflow).
This is how 'each' point in the transmission mixes old and new ATF.
Your cup of milk is now and diluted foggy water/milk mixture. Quit dreaming that ATF flow is a perfect loop.
Now, take the 3 glasses water/milk mixture that overflowed from the original milk filled glass, and use it to 'flush' another glass of milk(your TC). Repeat for VB, repeat for ATF cooler......
 
got ya. guess it just made sense that the flow was a nice loop. so at any point in time fluid that is hot is not always being pumped to the cooler to cool?? meaning it stays up in the trans?
 
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so at any point in time fluid that is hot is not always being pumped to the cooler to cool?? meaning it stays up in the trans?




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Nothing stays anywhere. The converter is where the highest heat production typically occurs. That's where the flow in my trans (a TF904 evolution - 30RH) heads to the cooler. It returns to bathe (lubricate and cool) the rotating parts.
 
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Don't ignore all the lubrication, cooling, VB circuits throughout the transmission, and any ATF working points. ATF flow is NOT a perfect loop.

The mixing of old and new is in the pan, throughout the transmission, and in the TC, constantly.

Take a glass(your ATF pan) filled to the brim with milk. And, slowly pour three equivalent glasses of water into the milk(collect the overflow).
This is how 'each' point in the transmission mixes old and new ATF.
Your cup of milk is now and diluted foggy water/milk mixture. Quit dreaming that ATF flow is a perfect loop.
Now, take the 3 glasses water/milk mixture that overflowed from the original milk filled glass, and use it to 'flush' another glass of milk(your TC). Repeat for VB, repeat for ATF cooler......




So any method trying to flush through the cooling hoses will encounter this? However when you push through the AT capacity (or a little more) via a flush the fluid color coming out does change drastically to clean looking bright red, but maybe at that point you are at 90% or 95% but not 100%?
 
A little more doesn't cut it. You would need 2x-3x the ATF capacity for a high ~90% flush.

If you want to see the %-rating or competence of the flush method that you choose, simply UOA the ATF directly before and after the flush. You can't judge an ATF's condition by looking at the change in colors. But, thats an easy way to 'market' the flush to the consumer. Even a 30% change on toasted ATF will drastically change the color on the dipstick.

70-80% is typical for an ATF flush REGARDLESS of all the marketing advertising bull saying it is complete. If the shop drains the pan and refills prior to starting the flush, then you'd be closer to the 80-90% range.
 
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