'09 2.4 Accord ATF flush

[mechanicx]

My brother's '09 Accord is coming up on 30K miles and I wanted to flush the ATF right. The Honda way is 4 drain and refills and going through the gears and locking up the converter 5 times between drain and refill (or you could drive the car around). This seems very time consuming, uses 12 qts of ATF, and no one really does all that.

Quote:
NOTE: The term “flushing” refers to repeatedly draining and refilling the trans with Honda Genuine ATF-Z1. Don’t confuse it with aftermarket flush systems. American Honda still strongly recommends that you avoid using them on any Honda vehicle. The original procedure was written for simpler A/Ts that readily upshifted when you ran the vehicle on a lift. But A/Ts have come a long way since then, and most of the newer ones balk at shifting past 2nd gear when on a lift, unless you work the shift lever a certain way. In light of all this, we thought it was high time that the A/T flushing procedure got a facelift. So here’s the latest word on flushing that works for all A/Ts:

1. Set the parking brake, and raise the vehicle on a lift.
2. Drain the trans, and refill it with Honda Genuine ATF-Z1. Refer to the applicable S/M or to ISIS for details.
3. Start the engine, shift into Drive, and release the parking brake.
4. Push down on the accelerator pedal to raise the vehicle speed to 2,500 rpm.
• If the trans shifts past 2nd gear, go to step 5.
• If the trans won’t shift past 2nd gear, keep the engine speed at 2,500 rpm and shift from Drive to Neutral and back to Drive. Then go to step 5.
5. Make sure that the trans shifts through all the forward gears and goes into torque converter lockup.
6. Let off the accelerator pedal, and press the brake pedal to drop the vehicle speed to zero. Shift into
Reverse and then into Neutral.
7. Shift into Drive, and repeat steps 4 thru 6 four more times.
8. Set the parking brake, and repeat steps 2 thru 6 two more times.
9. Drain the trans, and reinstall the drain plug with a new sealing washer.
10. Refill the A/T with ATF-Z1.


The other way is to flush out the cooler line. This seems like it'd be a lot faster and would only use about 6 qts ATF.

What I wonder is why does Honda think you need to go through all the gears and get converter lock up to fully distributed the ATF? Doesn't this suggest that just running fluid out of the line doesn't really distribute the fluid fully and won't get a full flush. I always believed a line flush did get most of the fluid out.

Also I think there is an inline filter on these ATs with a small paper element sealed inside. I know most don't get changed. It seems like you'd want to change it regularly. Also I'm just going to go with ZL-1, but I'm getting ahead of myself now.

 

[bepperb]

Either way will work. 6 quarts won't be enough for your method. Really, whichever you feel more comfortable with. I prefer the drain fill, since I work alone, don't mind running an errand to mix the fluid, and there's less potential for a huge spill. But the cooler line will work just as well.

 

[JHZR2]

Given the tendency of failure and lack of reliability on Honda ATs, Id do it right.

Of course, any little change in fluid likely pays dividends...

 

[mechanicx]

Yeah but do you see my point of cooler line flush vs multiple drain, drive, and refills? If a cooler line flush was equivalent, then for the drain refills all you should have to do is idle the engine not running through all gears and get lock up several times.

 

[mechanicx]

Here is the filter in the line. I don't know what the micron rating of that filter is or the bypass setting, but being as small as it is I can't imagine that filter going much more than 30K miles before clogging up and going into bypass mode.

AT filter

 

[bigmike]

I'd do a cooler line flush if you *really* wanted to do it the "right way." You can disconnect the return hose just before (or after) the filter you mentioned.

I put on a magnefine on mine, but I did so by accessing the panel underneath to get to the hoses there. It's a little bit of a pain, but it made the most sense due to the size of the magnefine filter.

You'll need more than 6 quarts, obviously.

I like just doing a drain/refill every oil change (roughly 7.5-8k miles). Seems easier.

 

[mechanicx]

If I flush at the cooler lines I will probably unhook both lines at the radiator to allow the cooler and the lines to drain out. It depends on access. I will probably stay with the OEM filter since it is a paper element and fits right. I look at the magnefine as more of a bypass filter and a magnetic filter but not sure. I realize it might take a little more than 6 qts with a line flush but I was just ballparking it based on fluid capacity vs. drain and refill 4x.

Does anyone have any thoughts on the idea that if idling fluid out the cooler line effectively distibutes fluid then you should be able to just idle between drain and refills too and not need converter lock up and gear changes. Maybe Honda automatics are a little different from others?

 

[Audi Junkie]

Originally Posted By: JHZR2
Given the tendency of failure and lack of reliability on Honda ATs, Id do it right.

Of course, any little change in fluid likely pays dividends...


That's only one single unit from years ago. So, accuracy...

 

[Audi Junkie]

In a newer unit, there is no need for a repeated flush. Service it by draining, fill it and drive a little while, then do it again.

The AT is now serviced.

If you want to do just one drain a year, every year, from there, that would be fine.

 

[mechanicx]

So you think at 30K one or two drain and fills would be good enough. And from thre on out 1 drain ~15K or 4 consecutive every 60K?

 

[benjamming]

If you only want to do a drain & refill (vs. cooler line method) then it would stand to reason that doing a drain & refill every 7500 miles would be better than 4 drain & refills every 30k miles. You use the same amount of fluid in both cases. However, the average "age" of the fluid is newer at any given time doing a drain & refill every 7500 miles.

 

[JakeR22]

You started early, drain a fill, done.

 

[Mau]

on the RDX I do a drain and fill every 25k, on my prelude I do it every 16k.

I get the fluid for cheap, and honda's track record with their auto's aren't the greatest.

 

[mechanicx]

Originally Posted By: benjamming
If you only want to do a drain & refill (vs. cooler line method) then it would stand to reason that doing a drain & refill every 7500 miles would be better than 4 drain & refills every 30k miles. You use the same amount of fluid in both cases. However, the average "age" of the fluid is newer at any given time doing a drain & refill every 7500 miles.


Yeah that makes sense but on the other hand at 30 K miles I'm left with 1/2 that 0 miles
1/4 has 7500 miles 1/8 fluid with 15000K 1/16 that has 22.5K..lol. That's if my math is right which it might not be. Anyway doing 4 once at 30k gives you more new fluid upfront and doing it every 7500k gives more new fluid at the end. Seems like a wash.

 

[benjamming]

mechanix,

You are keeping the fluid "freshened" which would seem like an advantage especially in a Honda that shears ATF like no one's business.