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View Full Version : 95% ATF change (not rutine 50%)



epic1400cs
07-22-2008, 02:44 PM
A couple of years back, I came across an article that explains how to change 95% of ATF, rather than approx half which Honda suggested in the workshop manual. It was written by A/T development chief engineer from M motors in Japan.
The trouble of normal method (drain half (3L), top up half(3L) ) is that there is always mixture with old ATF. By repeating half and half method, (50% - 75% - 87.5% - 93.25% ....) you can achieve high percentage of ATF change but you will need quite a lot of ATF (3L - 6L - 9L - 12L ....). This method enable to change about 95% with only 6L of ATF.
As I had to change ATF this year, I have tried this method and it seems to work very well. Here is how;

1) Drain old ATF as usual - drain from drain plug and close the drain bolt
2) Add the same amount of new ATF
3) Prepare for spillage and disconnect two tubes from ATF cooler which is at the bottom of the radiator
4) Prepare to receive old ATF coming out from both tubes, especially the one on the left when you look at the engine room from the front of the car
5) Start the engine and the rest of the old ATF will come out - this old ATF came from torque converter and valve body
6) After about 1 minute, when old ATF stop coming out, stop the engine
7) Connect pipes, top up ATF about 200cc less than the amount just came out
8) Start engine but without moving the car, shift into all the position P > R > N > D4 > D3 > 2 > P and stop engine
9) Check the ATF level and if needed, top up
10) Test drive for 10 minutes, check ATF level again

After this change, I can feel the shift shock became much smoother compare to the time when I did routine 50% ATF change.
To do this method you need to buy about 6L of ATF, which is the full amount of ATF inside the A/T but in reality I used slightly less than 6L hence 95%.

Demon1024
07-22-2008, 09:12 PM
don't have an auto, but that was a nice bit of info thanks!

Vanilla Sky
07-23-2008, 08:03 PM
Sounds like the "bucket method" with an extra step.

Oldblueaccord
07-24-2008, 08:28 AM
I kinda wondered too. I got a 92 Accord wagon now that I would like to get the fluid changed in sometime. I thought the pro shops use a machine and attach the lines to it to flush and refill but I never researched it as of yet.

I wonder how the dealership does it?


wp

epic1400cs
07-24-2008, 09:09 AM
Sounds like the "bucket method" with an extra step.
In terms of procedure and idea, the bucket method is very clear and straight forward - less step.
I thought this method is more economical as there is no chance of wasting the ATF - with bucket method, you need two people - one is watching the ATF out put and the other should be holding the ignition key.
Having said that, if 100% change is needed, bucket method with some extra ATF would be good.