Making a transmission firmer by changing the fluid

[ecco123]

Hello.

My Toyota automatic transmission is very smooth and confortable, but also very very lazy. The changes are slow and the torque converter slips way too much.

This is a common problem in these kind of Toyota transmission, I'm in a forum where many members solved it by fitting in a new valve body. I tried one and the results were impressive, still comfortable but much faster car, better engine braking and better fuel economy also.

The problem is that I can't afford the valve body now and a friend told me to try Amsoil super shift racing oil to get better response from the transmission.

The problem is that, in the Amsoil data sheet, it's stated that "AMSOIL Synthetic Super Shift® Racing Transmission Fluid is not recommended as a replacement for Ford Mercon®, GM Dexron® or Chrysler ATF+ type fluids in passenger vehicle and truck transmissions as it may cause erratic shift patterns, chattering or noise". My transmission is Toyota made, not a GM, but Toyota recommends Dexron II fluids (I'm using Dexron III now), so I think I could have problems. What do you think?

As an alternative, I've thought that the new Low-viscosity ATF could also provide firmer shifts and it's Dexron-VI, so I should be fine. What I doubt is that the improvement with the low viscosity one would be noticeable.

 

[Gary Allan]

I'm unsure what navigates your shifting selection, but in purely hydraulic transmissions, newer fluid provided better shifting due to being NEW and having not sheared yet.

I don't KNOW this but since the Amsoil Racing fluid is for use in TYPE F applications I'll speculate that it has friction material in it that would not be recommended for a trans not spec'd for it. This would work in 1975 ..not in 2009.

 

[ecco123]

Well, my Toyota is a 1991 model and it's transmission (A442F) is a slightly upgrade of the A440F, designed in 1984. It's an old fashion design with no electronics at all. Anyway, it the dipstick it says "use Dexron II".

 

[tomcat27]

I would not use
Amsoil's low viscosity fluid in your car unless it specified Toyota WS - which it does not.

 

[Gary Allan]

Well, you can try it, but it wouldn't be recommended. What I would do, IF I were going to do this, is buy half a dozen quarts of the Racing formula and exchange a quart at a time to judge the change in performance.

You will shed more metal with the Type F (like) compared to Dex compatible fluids.

I would prefer to save up for the valve body.

 

[Ken2]

Your Toyota has an Aisin-Warner transmission. These properly take Dexron-III. Dexron-II is long-obsolete and replaced by Dexron-III in everything except Hondas. Dexron-III is obsolete but still made by many blenders and widely available.

I don't know how to do what you want to do, except that valve body job you mention. What is the cheapest racing ATF you can find? You might try some of that, a quart at a time as Gary suggests, and see if you like the result. If you don't like the result, switch back to any Dexron-III fluid and save up for the valve body.

 

[3Toyotas]

Gary,

Don't you think the OP could see an improvement by just switching to Amsoil ATF?

 

[Gary Allan]

I don't think it will alter the basic characteristics of the trans. That's usually in the engineering end of it. If he's not seeing improvement with new fluid under normal temps, I don't think much can be improved upon.

That quart at a time thing was compliments of BuickGN. He mentioned that he used it to adjust shifting ..and when I thought about it, it sounded darn clever.

It's not something I'm interested in doing myself, but I don't have performance demands. I have only durability demands. There are plenty of kits to firm up my trans from $30-$100.

 

[brian12]

Mobil 1 Syn ATF makes for firm quick shifts. Have you looked for a shift kit for your trans?

 

[Kestas]

My trans rebuilder firmed up the shifts in my transmission to my liking. I believe it involves using a stiffer spring somehere in the valve body. This was for my 71 Cutlass.

 

[lexus114]

Originally Posted By: Kestas
My trans rebuilder firmed up the shifts in my transmission to my liking. I believe it involves using a stiffer spring somehere in the valve body. This was for my 71 Cutlass.


Thats an all together different animal dude.Probably a Turbo 350 or 400,very stout trannies!This new Metric junk out their is just that,junk!I know I`ll get a lot of [censored] for saying it,but hey,it is what it is.

 

[Kestas]

I know, that's why I posted the application. I don't know if something similar applies to Toyota transmissions sold in Spain. If the transmission is electronic then all bets are off.

 

[ecco123]

Thanks a lot guys.

Plenty of information, I'll try to order the responses:

1) That idea of adding one quart at a time looks atractive to me. The thing is, how much am I putting my transmission life span into risk?.

2) Ken, you talk about performance vs durability, but I've been told by Rodney, the guy that makes the valve bodies, that a firmer and faster transmission last longer as it generates less heat, plus the clutches slip less and less slippage equals less wear. I don't know if that sounds right to you.

3) Kits to firm up your trans for 30-100 dollars? where?. If I were ordering this valve body kit, It'd cost me about 600 euros (900 dollars) if I sum the valve body, shipping and customs. Plus another 150-200 euros of labour to mount it. This is the valve body by the way (not really, this is A440F, but my A442F is almost the same): http://www.automatictransmission.com.au/release.asp?NewsId=11360

4) The transmission is not electronic at all, is fully hydraulic, there is an electronic A442F that appeared in the market in 1993. Mine is a A440F with some minor upgrades. The A440F was designed in 1984.

 

[Gary Allan]

1) Probably none. The desire of firmer shifts means that you're into some performance oriented driving style. The service itself will probably dictate the life span. You may alter it to some degree with auxiliary cooling and filtration, but the general direction will be the same.

2) Rodney is correct. The limitation or elimination of co-applications will reduce most (normally) unavoidable wear. It won't increase the integrity of the hard parts to endure endless stress. Shifting is the number one normal wear factor. The rest is the service duty you subject it to.

3) My trans has been mostly unchanged since the later 60's (iirc). The only changes, outside of a lock up converter, have (mostly) been isolated to the valve body. All the applications (clutch/bands)are the same ..so only individual valve changes (only one, in fact, to firm up the 1-2 shift) are required. There are other kits that get progressively more involved up to the point of full manual shifting with SNAP shifting. Those can run $200+ U$D.

You seem to have found the only source for this modification. That's why the price is so high.

 

[ecco123]

It looks like I could give it a try. Just one last thing, in the Amsoil site is stated that "Note: AMSOIL Synthetic Super Shift® Racing Transmission Fluid is not recommended as a replacement for Ford Mercon®, GM Dexron® or Chrysler ATF+ type fluids in passenger vehicle and truck transmissions as it may cause erratic shift patterns, chattering or noise."

A don't know about chattering and noise, but the erratic shift pattern effect would only happen in an electronic transmission, wouldn't it?

 

[Gary Allan]

Let me ask you a question.

Does your trans shift better when cold?

 

[unDummy]

New fluid can make a tranny shift better. So, flush your fluid.
Check for any adjustments. If you have a kickdown, you can tailor it a little for a more aggressive shift.
DexronIII won't cause any problems.

Any competent transmission shop can modify a valve body, especially on an older transmission. You don't need to buy a 'marketed' kit.

On older transmissions, seals are worn tired and leaky. You might need to reseal the tranny or use a high mileage or thicker ATF to make up for the 'leakage'.

 

[ecco123]

Gary, I can't see any difference between the shifts when is't cold and when it's hot.

The transmission has been rebuilt about two years ago, so the seals should be ok. Also, the fluid is new, just 3000 miles on it.

Yesterday, my truck has been driven by a friend with experience in automatic transmissions, and he thinks that the shifts are allright, not very fast but ok, but the problem he finds is the excessive slippage of the torque converter.

I've seen this product from the same place where they make the valve body kits that maybe can make an improvement:

http://www.automatictransmission.com.au/release.asp?NewsId=12101

The stock transmission only locks up the Torque Converter in 4th, and, when the modified valve body it also locks up in 3rd.

With this switch, I could lock it up in 2nd and 3rd manually and stop that slippage. Not as comfortable as having the valve body, but sure much cheaper. By the way, what would happen if I forgot the torque convertor locked and the transmission shifts?

And, a 3rd gear with the torque convertor locked would be like having another gear between 3rd and 4th, wouldn't it?

 

[unDummy]

It gives you more control.

Unlocked TC cushions the shifts so you will feel it more, and there will be more wear to the clutch/bands during each shift if you forget.

With it locked, it'll stall at a stop.
With it locked, the transmission should run cooler. You'll also have a more noticeable gas pedal affect(compression braking, lurching...).

 

[ecco123]

Yes, I imagine is not very good to change gears with the Torque Converter locked up.

I'm mostly driving in 3rd in secondary roads and 4th in the highway, so I could lock it up when I'm driving in 3rd and unlock it when I need a kickdown or switching to 4rd.

Also, there is huge jump in these cars from 3rd to 4th, maybe a lock up convertor would fill this void?