There's no pan to drop, just a drain plug.

As for the logic, unless you do a drain and fill multiple times in a row you aren't getting new fluid, but you are keeping the level of fresh additives at the right level.

 

No, you do not simply add some new fluid, rather you flush it all out and replace with new for the first time at 30k miles for the Fits. Since the tranny and the converter hold 8 quarts and you can only replace it 2.6 quarts at one "flush and fill", the dealer recommend to repeat it 4 times to get it all out for the first 30k miles: drain and fill up with new Honda DW-1 AFT 4 times where the first 3 times you drive around for 5 minutes then drain it, then keep the forth one for good. After the first 30k 4 times "flush and fill" process, they recommend to replace it every 15k there after. Well, stop by your dealer and ask the parts department technician, maybe they can provide some confirmation of this.

 

Was there a change in the ATF fluid recommendation halfway through the model run? I noticed one poster say that the 2010 calls for ATF-1 and has been discontinued. I have a 2012. I can tell you (later) what the manual recommends but want to ask if anyone has a complete picture of the change, if any.

I do not have tons of faith in Honda ATs and would likely, myself, change the ATF (once, not a flush) every 15,000 miles. Very cheap and easy. Any sooner seems like overkill, though.

 

IIRC 2011 and forward get dw1. And dw1 is the recommended fluid to use for all transmissions that used z1. However, unless there has since been an update, there is no reason not to mix the older z1 with dw1. That is, even if your car has z1, you don't need to worry about doing more than a single drain and fill; the two fluids mix fine.

Obviously though, you should not use z1 in a car that calls for dw1

 

I'm sure the parts department would gladly sell me the requisite number of bottles to do that, but the fsm only calls for single drain and fills.

 

Perfect. Thank you.
Not coming up on this quickly .. plenty of room left before 15k miles (weekend driver only) ... but now I know what to do when I get there.

 

There's got to be a better way. Someone above mentioned you get the "additives" right, but what about the grit in the tranny from breakin. I'd think that would be the more important reason to change your fluid, and this method doesn't seem to do much for that.

As far as the flush and fill ~1/4 of the fluid 4 times

First fill new fluid : 1/4 : + .25 new fluid

Second fill new fluid .25*(.75 old fluid) : + .1875 new fluid
Minus new fluid lost in second fill : - (.25)(.25 new fluid) : - .0625 new fluid

New fluid after second fill : .25 - .0625 + .1875 = .375 new fluid

Third fill new fluid .25*( .625 old fluid ) : + .15625 new fluid
Minus new fluid lost in third fill : -(.25)(.375 new fluid) : - .09375

New fluid after third fill: .375 - .09375 + .15625 = .4375 new fluid

Fourth fill new fluid .25( .5625 old fluid) : + .140625 new fluid
Minus new fluid lost in fourth fill: -(.25)(.4375 new fluid): - .109375

New fluid after fourth fill: .4375 - .109375 + .140625 = .46875 new fluid


So, after four "flush and fill" procedures, assuming equal distribution of fluid/ additives etc. We have replaced .46875 (less than half) of our fluid with new, and managed to spend a lot of money on AT fluid.

Someone check my math, but there has to be a better way. I think flushing some of the addtl. fluid from the radiator, as I've seen elsewhere is a good course of action, but is there really no way to drop the pan on these cars?

Can anyone with a shop manual chime in???

 

Shop manual just calls for drain and fill. Once. As for particulate matter, there is a filter.

 

After four drain/fills you should be @ about 90% new fluid. It's closer to half each time... (check my math):



As for the factory manual, here's what it has to say...

I noticed an improvement (smoother shifting and less noise) after the 1st drain/fill to DW-1 from Z1 @ 30k. Did a 2nd about 10K later, no noticeable difference. Will do the 3rd and so on after another 30K. This is my only departure from the MM: my rational is to use the newer fluid.

 

Your math looks right. I made some incorrect assumptions.

I still do think there is a better way, but currently at 26k, I may do a single flush/fill since that's better than nothing. Do you have any experience changing the filter located under the airbox, and do you know if that is the only filter?

 

there's an internal screen, but that's for larger particles. No replacing that short of a rebuild. The plug is magnetic so it'll have lots of interesting metal on it to clean off.

I wouldn't worry about the in-line filter (cooling line behind the transmission). It's not a maintenance item. But it's not difficult to replace if it makes you feel better about it.

 

If you really want to replace most of the existing ATF fluid, drain from the ATF transmission line going into the radiator or coming out from the radiator. Search the forum as there are couple good DIY's.

 

I'm closing in on 30000 miles (50000km). so being OCD myself, I'm starting to think about my transmission fluid.

After reading this whole thread, the general consensus seems to be 1x drain/fill every 30k if you want to be really nice to your AT. 4x drain/fill if your fit came with z1 originally. Would someone please confirm this?

I wouldn't say I drive in severe conditions, but I do want my AT to last as long as possible, so I want to be really "nice" to it by servicing it more often then called for. I have no intention to sell off the car, and plan to keep it till it dies. That said, I don't feel the need to go crazy overboard with the fluid(ie. full 4x at 30k)


Is there a specific part number for the drain plug and washer? I think it might not be a bad idea to replace the plug every few years since the magnet might weaken over time.

Do the filters need to be replaced as well? From what's been said, it looks like these are non service items and that the magnetic plug does most of the filtering.

Thanks for your help guys.

 

um. prozak helps.

Otherwise (and probably healthier) pick up crush washers from Honda. They're about $3, pn 90471px4000 (18mm). ask me how I know. The plug is not a maintenance item. Neither is the filter (on the outside back of the transmission).

 

Sounds like a good plan, but don't waste your labor just because you feel like it.
I'd do the service at with every oil change, to do both services at once. If you're OCD and the thought of z1 bothers you; do the service the next 2 oil changes in a row; then maybe skip to a longer interval after that.

As for me, I use a mityvac; so no messing around with the drain plug is needed.

 

Well I've done 3 oil changes so far, almost about time for the 4th. I think it wouldn't hurt to do a 1x drain and fill once I get to 30k miles.

I'm pretty sure mine comes with dw1 as it's a 2012 model, so it's really more just pure OCD kicking in.

Steve, thanks for the part number. Severe service made a good point I think when he said the heat and cold could weaken the magnet in the plug overtime.

Since we get a temperature variance of 70C here (-35 to + 35) from summer to winter, I wouldn't doubt that there is a lot of stress being put on it. Of course that also could be said for everything in the car.

 

Here's an article on magnetic stability of various materials. They recover from cold when returned to normal temperature. Heat seems to be an issue over 150C. I wouldn't worry about it.

 

After 1 or 2 changes, if your transmission is still sloughing off metal, then you have bigger problems to worry about then a magnet

 

Not changing all the fluid is a joke. Also, not changing the filter. The magnet, will not collect particles off the clutch discs. The filter does.

It really isn't that hard to remove a cooling line, run the motor and catch the fluid in a container, as you add new fluid, while it drains.

If you insist on adding new fluid to old, why run engine (mixing new fluid with old) very long. I would run it as long as I would think it takes to pump the new fluid form the sump area. Then drain again, and repeat 4+ times.
Much more effective to do it by removing a cooling line.

But don't go by what a retired auto transmission mechanic says. Do, what the "experts" on the forum say.

 

While I'll stick to the perspective you can do whatever you want it's your car;
I've never gotten the logic behind the change-it-all or do nothing folks.

The people who swear by changing all the fluid never really address the logic that if the fluid is so bad, what is the state of operation right before you performed the change? You've been running on near-bad fluid!

In the chart posted by steve244, he only looks at fluid replaced.

A better chart would be a chart of like fluid capability (in % of newness) and considering the degradation between the drain/fill changes.
So like, assuming the fluid degrades 5% between intervals.

100%->95 (perform d/f)
98%->93% (perform d/f)
...
Then eventually you'd reach a steady state where your worse case fluid is at "90%" capability.

95%->90% (perform d/f)
95%->90%

If you take on the logic that oil is "bad", which is why you need to change it all, that means for long periods of time you are running at much worse fluid.

I understand this probably isn't true in the state of the real oil's capability;
But in terms of the thought experiment to try to understand the throught process, the change-it-all logic doesn't make sense once you follow it through.