ATF for GM 4-Speed Automatic Tranny

[Anduril]

I bought a 2000 Cavalier a couple months ago with the 4t40e 4-speed automatic. It had 47k on the clock at the time, I've put almost 5k on it since then. I'm sure the ATF has never been changed (the manual says it's a "lifetime" fill but since I'm here, I obviously don't believe that) and I'd like to freshen it up a bit.

I'm not sure which type of fluid this transmission requires, although I'm fairly certain it's DexIII, and I don't know much of anything about what's even out there in terms of synthetics. I don't plan to flush this transmission, but rather to do a few consecutive pan drops to get it all out. Does anyone know if this transmission has a drain plug, or if I should look into adding one.

 

[dwendt44]

You'll have to add a drain plug, none there now.
Dex III is spec.. You can get Dex VI if you look hard; it's new and back ward applicable. Dealer has it but it's expensive and just a synthetic blend.
I just did my 05, 8 qts Mobil 1 ATF, a Fram trans filter and a bit of grunting and cussing.
The T gasket is re-useable so be carefull.

 

[brianl703]

The 4T40E has a level checking plug. You are supposed to remove this with the engine running to check that the fluid is at the proper level. If the fluid is level with the hole then it is at the proper level.

What happens when you remove it without the engine running? About 4 quarts of fluid come out. So it can double as a partial drain plug.

Also the 4T40E has a pan that can be removed and a filter that can be replaced. Removing the pan will get 7 quarts of fluid out.

 

[JohnBrowning]

Seeinghow you are doing this I would go with either a synthetic DexIII like Amsoil,RP,Mobil 1 or Dex VI. These are going to last much longer then the factory fill ever did and will extend the life of the transmission. I recomend droping the pan and replaceing the filter. A kids hard plastic smimming pool works great for catching the mess! If you are not interested in synthetic consider Valvoline Maxlife ATF!

 

[Anduril]

So for those of you who have experience in this area, what is the proper procedure for a pan drop on this transmission to ensure that the fluid level is correct after the whole thing is said and done? I am definitely going to change the filter (where would be the best place to get one from?) and should be adding a drain plug to the pan as well. Maybe I wasn't looking in the correct section, but the selection of ATF at my local Wal-Mart seemed quite limited.

 

[brianl703]

After removing the pan and re-installing it, add 7 quarts of fluid through the red or black filler cap on top of the transmission.

Then start the engine and let it run for 30 seconds with the selector in each gear (drive, neutral, reverse, 3,2,1 etc). Let it idle until the transmission pan feels warm to the touch, about 105F. At that point, remove the level checking plug. If any fluid comes out then the level is correct, reinstall it. If no fluid comes out add some until a small amount does. Reinstall the plug.

The transmission must be level during this operation so you will need to jack the rear of the car up too OR you may be able to reach the level checking plug without jacking the car up at all. You can use a carpenter's level to check that the transmission is level.

 

[brianl703]

Incidentally I used Mercon V in this transmission when the fluid was changed in it. Dexron VI was not yet available.

 

[JTK]

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