The down-low on ATF types

[SaddleMtnMan]

Picking an ATF type for a 91 auto. Before someone flames me, yes, I have spent an hour inside the little search bar reading old posts.
I know the original spec is Dexron II, something that's been dead since 1993.
About 90% of posts here are religious fanatics about using Honda Z-1 ATF, which is long since discontinued, so that's what leads me back to here.

I see plenty of people recommending to stick with the current Honda DW-1 ATF, but another half will immediately say it doesn't perform well in our older 4-speeds due to it's low viscosity. The more I read, the more confused I end up.

Quite a few posts now recommend Valvoline MaxLife, a Dexron VI/MERCON-LV equivalent.
From what I understand. DexVI is the last Dexron fluid designed to be backwards compatible with previous Dexrons (III and II mainly). so is the Valvoline (or other dexVI equivalent I can get my hands on) a good pick here? I'll probably just grab a jug and run a drain&fill this weekend regardless of responses to see how it feels, but personal ancedotes welcome!

[Raf99]

I ...... never thought it made a difference. I just use OEM. But this also depends on where you live too (hot or cold), just like engine oil.

[SaddleMtnMan]

I ...... never thought it made a difference. I just use OEM. But this also depends on where you live too (hot or cold), just like engine oil.

Maybe it doesn't. I'm used to overthinking fluid choices 'cause I come from the Subaru realm where using the slightly wrong type of gear oil will ruin your synchros lol, so I've learned to be paranoid. But I guess these old beater 4 speeds really don't care that much.

F**k it, i'm throwing valvoline in there, my stupid dealer monopoly wants $19/qt for DW-1 and I'm not about that. Forget I even asked this question, will report back if something janky happens.

[adecanmin]

I've been using Valvoline for years. I change it often. 381000 original auto trans.

[SaddleMtnMan]

I've been using Valvoline for years. I change it often. 381000 original auto trans.

I take that as a good vote of confidence in Valvoline. Thanks!

I just did the first drain&fill this morning, going to drive to town for an event, then do another drain and fill when I get home.

[director.cb7]

Good afternoon, on Monday 01/09/2023 I will do a partial oil change on my gearbox, here in the whatsapp groups that I participate in, they recommended Dexron III, and I will add two additives, "Lubegard Instant Shudder Fixx", which is for bumps, and I will add the Lubegard platinum which is for composite discs and the like. I'm very worried about my gearbox, the car barely started when I got it! I did a complete engine on top and bottom, cooling, changing several parts as well. About my gearbox, reverse engages when it wants to, I think when the car is hot, when it's cold, it engages normally
Has anyone done a complete overhaul on this car? quiet to do? I await opinions!

[director.cb7]

So SaddleMtnMan what did you decide about your ATF? how was the change after the exchange? Did you do partial or total? Here in the groups, I was recommended to do 3 partial changes, every 500km, change 3 liters to clean and filter the automatic transmission. If not, I'll have to go for a new exchange

[SaddleMtnMan]

So SaddleMtnMan what did you decide about your ATF? how was the change after the exchange? Did you do partial or total? Here in the groups, I was recommended to do 3 partial changes, every 500km, change 3 liters to clean and filter the automatic transmission. If not, I'll have to go for a new exchange

I did one drain, which came out quite dark looking, refill, drove it for 100 miles (one commute cycle), drained and filled again. No "exchanges" with a machine.
Took about 2.4qt (2.2L) each time. Second change was almost no noticable darkness so I left it at that. I'll probably do a third at the next oil change to be safe.

No issues whatsoever on the valvoline maxlife and I've put about 2000 miles on so far, shifting feels as good as it ever has. Which is to say, a little sharp once in a while when you're in a weird part of the throttle, but positive with zero slips. I probably need to do a cable adjustment anyway so that's likely adding to the transmission weirdness.

Notably I had a ton of crap on the magnetic drain plug. Make sure that gets THOROUGHLY cleaned. And if it's not a magnetic plug, go get an OEM one.

reverse engages when it wants to, I think when the car is hot, when it's cold, it engages normally

that could be valve body and shift solenoid issues tbh. Do the fluid changes first and see if it helps.
If it really is screwed i don't think MPXA transmissions are hard to find. And they're fairly small and simple so not terribly hard to get inside and change clutches and solenoids on. Do some more searching, I *know* there's a few overhaul threads floating around here.

[director.cb7]

I did one drain, which came out quite dark looking, refill, drove it for 100 miles (one commute cycle), drained and filled again. No "exchanges" with a machine.
Took about 2.4qt (2.2L) each time. Second change was almost no noticable darkness so I left it at that. I'll probably do a third at the next oil change to be safe.

No issues whatsoever on the valvoline maxlife and I've put about 2000 miles on so far, shifting feels as good as it ever has. Which is to say, a little sharp once in a while when you're in a weird part of the throttle, but positive with zero slips. I probably need to do a cable adjustment anyway so that's likely adding to the transmission weirdness.

Notably I had a ton of crap on the magnetic drain plug. Make sure that gets THOROUGHLY cleaned. And if it's not a magnetic plug, go get an OEM one.



that could be valve body and shift solenoid issues tbh. Do the fluid changes first and see if it helps.
If it really is screwed i don't think MPXA transmissions are hard to find. And they're fairly small and simple so not terribly hard to get inside and change clutches and solenoids on. Do some more searching, I *know* there's a few overhaul threads floating around here.

How good is your story.
I made the partial exchange on Tuesday, 01/10/2023;
Reverse is engaging normally with no problems now, thank goodness!
I'm going to use the car and run it until 02/10/2023 then, 1 month just running it, to carry out a new exchange. Since you made an exchange with 100 miles, I found it very little kkk but as it worked, great

As for the electromagnetic you speak a magnet? and put it in the plug underneath to stick/fish the soot and mesh, correct? I'm going to run after this magnet to accomplish this.

[SaddleMtnMan]

How good is your story.
I made the partial exchange on Tuesday, 01/10/2023;
Reverse is engaging normally with no problems now, thank goodness!
I'm going to use the car and run it until 02/10/2023 then, 1 month just running it, to carry out a new exchange. Since you made an exchange with 100 miles, I found it very little kkk but as it worked, great

As for the electromagnetic you speak a magnet? and put it in the plug underneath to stick/fish the soot and mesh, correct? I'm going to run after this magnet to accomplish this.

The only reason you need to drive after a drain and fill is to exchange the fluid sitting inside the torque converter, which does not drain from the pan. Theoretically this fluid is exchanged within a few minutes of starting the car.... even very old, used up fluid should not be leaving any kind of "deposits" that the new fluid has to wash away, and if it does, your trans is probably in incredibly bad shape. Thus 100mi was plenty for me.

The magnet is part of the OEM drain plug, should be attached to the end of the actual drain plug itself, not something you need to add. It will be a black bit on the interior end, usually will have some grey goop stuck to it (this is wear metal out of the trans)
Some aftermarket drain plugs don't have it though. Highly HIGHLY recommend getting an OEM one with the magnet if you do not have a magnet plug, this is the only form of "filtration" the trans gets without adding an external filter in the cooler lines.


Reverse coming back is a very good sign though! Your old fluid was probably just so sheared out that it wasn't thick enough to actuate the reverse clutch or something. Keep changing it, she'll survive.