Swapping ATF?

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Hi guys... so I've been a BITOG member for a while now, and I seem to think I know my engine oils quite well at this point. As for ATF, though, I am totally in the dark. Don't understand the first thing about it...

Anyways, I want to swap out the ATF in my 1992 Lexus SC400. I understand it has an Aisen-Warner A340E transmission.

So, somebody help me out. What do I need to know? How do I choose the correct ATF for my application? And how is it done? Is it safe to do if it has never been done before? The car only has 135,000 KM on it (approx 84,000 miles)?
 
Choose the correct ATF by reading the owners manual(or dipstick), and find an equivalent.
Plenty of good ATFs available at local stores and online.
 
If you look in the Amsoil website, they have a function to tell you what fluid to use for any recent car. Your car takes their synthetic ATF (ATF is a Amsoil model number), which is very good fluid.

However what is the history of service for this AT. You should probably drop the pan, clean it and replace the filter. If the current fluid is very dirty and the pan and filter are too, then I might not switch it to Amsoil ATF at first, rather switch it to regular ATF, then when that stays clean for awhile you can switch it to synthetic.
 
i think i will probably order an ATF pan kit with the gasket and filter so i can drop the pan and get it cleaned.

whats the difference between the different kinds of ATF's like mercon and dexron and all those other ones?

someone else on this board (sonyman) has the same tranny as me and he swapped in Amsoil ATF, so i think its safe for me. if so, is that a good synthetic ATF, or are there others i should consider too?
 
Typically the differences between the Mercons and Dexrons is frictional properties, heat resistance, etc. Judging from the year, I wouldn't be surprised if yours is just plain DexronIII/Mercon.

Do a pan drop, filter replacement, with some cheap ATF (as long as it is the correct kind) and drive around for a few thousand miles. If everything turns out ok, I'd recommend doing a full flush with a synthetic ATF that fits yours, which Amsoil ATF does.
 
If you aren't ready to spend all the money on Amsoil ATF, but want Synthetic, buy Mobil1 Mercon V IF you car states that Dexron II/III is suitable.

Also, Dexron VI might be a good choice if you want full synthetic and your AT takes Dexron II/III ATF.
 
I feel Amsoil ATF is a good value ATF even considering its cost given how long its slated to go for (50K severe and 100K normal).

However one needs to understand the condition of the AT before introducing Amsoil ATF or any synthetic.
 
Quote:


Typically the differences between the Mercons and Dexrons is frictional properties, heat resistance, etc. Judging from the year, I wouldn't be surprised if yours is just plain DexronIII/Mercon.

Do a pan drop, filter replacement, with some cheap ATF (as long as it is the correct kind) and drive around for a few thousand miles. If everything turns out ok, I'd recommend doing a full flush with a synthetic ATF that fits yours, which Amsoil ATF does.




why not drop the pan and go straight to amsoil atf?
 
I am guessing that they were trying to save you some money, and use a less expensive fluid for a short "flush" run.

Mercon (now Mercon V) is a FORD specification.
Meaning that FORD came up with the specification, requirements, and licensing to companies to sell fluid that states "meets Mercon Specification" on the lable.

Dexron is a General Motors, GM, specification.
While the specifications may be different, it is possible for 1 fluid to meet both Mercon and Dexron specifications.

A good start, as UnDummy mentions is the transmission dip stick and / or owner's manual.
Then you would look for a fluid that lists that on the label.
I would also STRONGLY recommend checking to see if Lexus has issued any Technical Service Bulletins, TSB's, for your vehicle.
This is particularly good to do for our older vehicles.
As new, often improved, fluids come out, manufacturers often issue TSB's stating that one SHOULD or MAY use the newer specified fluid......and easy one would be Dexron II may have been the latest specification when one's vehicle was manufactured, but then Dexron III came out.....which is an improved fluid that would be an upgrade to the Dexron II.

However, an newer fluid is NOT automatically better for an older vehicle......as in the case of ATF for the newer Constant Velocity Transmissions not being appropriate for other transmissions.

Another thing to take note of.
Some "smaller" manufacturers of ATF will state "recommended for Mercon V (or Dexron xx) applications"
This is because they have not paid the money to be a "licensed" fluid...which requires royalty fees, and .....very expensive testing processes to get.
This does not necessarily mean that they are not good fluids, just that the costs are very substantial for a smaller company.
Amsoil and Redline are 2 companies that manufacture high quality fluids, that may not be "licensed"....but are certainly not "no name" cheap knock off's.
 
To the people who mentioned a filter replacement: There is not filter in this transmission. There is a metal screen which can be cleaned, but as a routine, I would not even bother dropping the pan if the fluid isn't in terrible shape. Just do several drain and fills with Amsoil ATF or with Toyota T-IV, or do the radiator exchange method. By the way, an excellent resource for your car would be the following site: http://www.lexls.com/tutorials/transmission/ . I linked directly to the section applicable to your current needs but feel free to browse around in the other sections. Anything drivetrain-related will be 99% the same. If you have any other questions don't hesitate to ask.
 
Quote:


I am guessing that they were trying to save you some money, and use a less expensive fluid for a short "flush" run.

Mercon (now Mercon V) is a FORD specification.
Meaning that FORD came up with the specification, requirements, and licensing to companies to sell fluid that states "meets Mercon Specification" on the lable.

Dexron is a General Motors, GM, specification.
While the specifications may be different, it is possible for 1 fluid to meet both Mercon and Dexron specifications.

A good start, as UnDummy mentions is the transmission dip stick and / or owner's manual.
Then you would look for a fluid that lists that on the label.
I would also STRONGLY recommend checking to see if Lexus has issued any Technical Service Bulletins, TSB's, for your vehicle.
This is particularly good to do for our older vehicles.
As new, often improved, fluids come out, manufacturers often issue TSB's stating that one SHOULD or MAY use the newer specified fluid......and easy one would be Dexron II may have been the latest specification when one's vehicle was manufactured, but then Dexron III came out.....which is an improved fluid that would be an upgrade to the Dexron II.

However, an newer fluid is NOT automatically better for an older vehicle......as in the case of ATF for the newer Constant Velocity Transmissions not being appropriate for other transmissions.

Another thing to take note of.
Some "smaller" manufacturers of ATF will state "recommended for Mercon V (or Dexron xx) applications"
This is because they have not paid the money to be a "licensed" fluid...which requires royalty fees, and .....very expensive testing processes to get.
This does not necessarily mean that they are not good fluids, just that the costs are very substantial for a smaller company.
Amsoil and Redline are 2 companies that manufacture high quality fluids, that may not be "licensed"....but are certainly not "no name" cheap knock off's.



For his vehicle there is a TSB listing replacement fluids, since his car was originally spec'ed for Toyota T-II transmission fluid. The replacement is T-IV, but the actual spec is the JWS 3309 one, so any fluid that meets that spec should work. However, the only 2 fluids I would personally use, and have used successfully, are genuine Toyota T-IV and Amsoil ATF, with the latter being my preference.
 
hey sonyman, your link and info has been AWESOME! thanks, man. i'm probably going to order a case of Amsoi ATF and follow the radiator method. should i even bother dropping the pan and cleaning it out and cleaning the mesh screen?

what did you do?

and why do you like the Amsoil ATF? is it smoother?
 
oh, and while i'm at it... did you change the fluid in your rear differential too? i was thinking of doing that as well. not sure what kind of fluid to use. hoping Amsoil has something good for that application too. perhaps their MTG or AGL? what does our differential spec? probably 75W-90 gear oil.
 
If your fluid looks dark, it may not be a bad idea to clean the screen. My fluid was only slightly oxidized when I first bought my car, so I didn't bother. I have just done 3 drain and fills since then through the drain plug. I chose Amsoil ATF because it's simply the best transmission fluid you can buy that will work in this application. The shift quality is, and should be the same as if you used T-IV, but the Amsoil will hold up better to the test of time. The only thing I would deviate from if you do decide to drop the pan is to use FIPG instead of an actual gasket. FIPG is easy to use- just run it along the edge of the pan in the groove and draw a circle around each screw hole. Your pan was sealed with Toyota FIPG from the factory, a liquid gasket.

I did change my differential fluid when I purchased my car. I used Red Line 75W90 but if I had to do it again I would use Amsoil SVG 75W-90. Red Line gear lube is a fine product, but since that new white paper came out, Amsoil appears to be the better product.
 
I have used Amsoil Universal ATF in some Toyota T-IV transmissions, and I am VERY pleased with the result. Even the butt dyno indicated an improvement in one Toyota Solara 4 cylinder.
 
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