Which transmission fluid?

[TazMan]

I just bought a 2003 GA GT with 78,000 miles and I want to do a transmission fluid/filter change. I did some searching to see what kind of fluid to use. Some people say dextron 3, some say dextron 4, some say 6? What kind of fluid goes in this thing? What brands do you recommend? I noticed if I start it and just drive without warming it up, the shifts aren't quite as smooth as they are when it warms up. It always shifts fine with no jerking, slipping, or problems of any kind, but after it's running for just a minute, I can't even feel the shifts. I'd like to use the best fluid I can get.

[3400-95-Modified]

You can get away with D-III, but you can also use D-VI, I'm using 6 on my car and its a 96 transmission.

[Z26-T]

Dex 3 or 6 will work just fine. Dex 6 costs more and has some upgrades from dex 3, but with your car it is not needed. I'm using 6 in my 95 without any problems, but that's because I can get 6 for free. If I had to pay I would probably use 3 because that's what gm wanted at the time.

DEXRONŽ-VI can be used in any proportion in past model vehicles equipped with an automatic transmission/transaxle in place of DEXRONŽ-III (i.e. topping off the fluid in the event of a repair or fluid change). DEXRONŽ-VI is also compatible with any former version of DEXRONŽ for use in automatic transmissions/transaxles. Courtesy of GMSI

Also doing some more research, it says things such as clutch stability improves 100%, clutch durability improves another 120%, and the stability of it improves 200%. But it's all choice what you want to use.

[3400-95-Modified]

I just dropped 71 bux on Castrol Dex 6... A case of 12 since I had to pull my trans.

[Z26-T]

I'm not sure the exact price difference from dexron 3 and 6, tried a little search online, but couldn't find a good comparison. I'm pretty sure at my work we charge twice as much for 6 than we did for 3. If not twice it's pretty close. But the fluid is supposed to last 100,000 miles and still have it's intergrity. With how we drive our vehicles... most of us need the extra help . If you service your vehicle regularly, and drive it like a normal person (not many of us do ) dexron 3 will probably work just fine. But if you need all the added protection you can get you may want to spend the extra cash and have the possiblity of your tranny lasting longer, spend the extra money. $$$ is the bottom line.

[3400-95-Modified]

Yeah I'm not nice to my cars... LOL

Plus this one is an expected 280-285hp engine.... its gonna need all the protection it can get.

[TazMan]

Oh so they're all just upgrades over the Dextron 3. That makes sense now.

As far as price, I'm willing to spend whatever I have to to make sure I get the best fluid I can in there. Do you think that just a fluid and filter change is sufficient and do you know about how many quarts I'd need for this? Do any of these come in a synthetic version? Is synthetic good or bad for these tranny's? I read somewhere that these transmissions sometimes act funny when you go to synthetic or use a fluid other than GM brand. Is this true or just some bad experiences had by a few people with already worn transmissions? Thanks everyone for all your input and for all this great info.

[Z26-T]

Lol, GM brand . Not many dealerships have actual GM brand oil coming out of their pumps.

Not sure about using synthetics in these, don't see any problem except a more highly possible chance of having seals leak. (it's like using regular oil in a car it's entire life, then when you're above 100k you decide to use synthetic... stuff starts to leak). But i'm not sure. With these electronically shifted transmissions you can probably go a little too crazy and use stuff that flows too well... Personally I'd use just dexron 6 if I wanted the "best protection" and put some shift additive in it. I don't know what most of the guys around here like, I just use BG stuff, which is only available at some shops/dealerships. (http://www.bgprod.com/home.html) But a lot of guys will probably argue with me and say that lucas makes the best trans additive, or castrol, or valvoline. I just like BG because it's what I use daily and havn't had any problems with it, or had any come backs from it.

I use synthetic in the dragster, but that has a to do with the trans brake... And nothing about it is electonically shifted. Lots of guys are now using hydraulic jack type fluids in their dragsters as well.

[TazMan]

Thanks. I think I'll also get the Castrol Dex 6. Will I also need to get 12 Quarts for a filter and fluid change?

[pocket-rocket]

Just don't use the Lucas trans stuff. I threw that in my 91 when it still had an auto, and the TCC only worked 50% of the time after that. Then half of the time it did work, it would slip, so I would have to make it disengage and go back in again so I didn't burn anything up.

[IsaacHayes]

Only additive I used was GM Automatic Transmission Seal Conditioner for $6 at the dealership and it cured my problems.

[pocket-rocket]

I was trying to get it to shift better and trying to get it to keep from self destructing at the same time. At that point in time it was my DD, so I was limited in time how long it could be down, and I wasn't brave enough to tear it open as well. I had even gone as far as to put a trans cooler made for a 16k lbs truck on it to make sure it didn't get too hot, lol. We all know how the 4t60-e reacts to DOHC... The car had gone through 3 before I put the 284 in there at 130k miles.

[loner666]

^ Im working on my 3rd 4t60e for the car right now. lol. My cooler is rated for 17.5k GVW and I have a second one just like it that Im thinking about installing because my trans is STILL getting hot. Probably from the tight fight under the hood :-/



Anyway. For a pan drop and filter change you'll only need about 5quarts of fluid