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What automatic transmission fluid to use



02NavyBlue said:
That's the stuff I used, but by Valvoline brand (dex/merc III) All 3 you posted will work though. The VI is the newer fluid and is partially synthetic which is iffy sometimes on older worn transmissions.
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Was looking at valvoline max life dex/merc. I've read a lot of good reviews. However, on the back of the jug it says it's compatible with dex ll, dex lll and dex lV. I'm gonna be changing my tranny fluid very soon along with an Intense-racing shift kit and from what I've read I think I just want dex lll I can't seem to find the blue jug in post #23 just the red jug. Sorry to thread jack but don't see a point in making another thread for the same reason.
 
smoke14 said:
Was looking at valvoline max life dex/merc. I've read a lot of good reviews. However, on the back of the jug it says it's compatible with dex ll, dex lll and dex lV. I'm gonna be changing my tranny fluid very soon along with an Intense-racing shift kit and from what I've read I think I just want dex lll I can't seem to find the blue jug in post #23 just the red jug. Sorry to thread jack but don't see a point in making another thread for the same reason.
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The red jug is the same thing but used to be with an additive pack. Recently the red jug changed and is now synthetic. You mean you can't find the blue jug in person at the store, right? (since I posted the link)
 
why would you get anything that says dex compatible? get dex vi. its a better fluid then dex 3 and its a GM retrofit to the ****ty dex 3.
 
Like I said it's a matter of opinion, use what you want.

It's the same debate as conventional motor oil vs synthetic...Dex vi uses synthetic technology whereas dex II does not. Plenty of people around here buy the cheapest or on sale conventional and just keep up with 3k mile intervals, others prefer synthetic and will always use that. Both work. With regular change intervals both can take 3800's to 200K + miles. Dex III can take the older 4t65e's to 200K + as well.

I guess I go both ways, synthetic in the motor and dex III in the trans. For reasons though, I had issues with the pcs at the time, even still I notice the pressure being different at high vs low temps. Our 2003 impala's trans had input clutch sealing issues for 2 random occurrences, then never happened again. I'm definitely using dex III in that one. And lucas. (didn't use lucas in mine since it was a solenoid issue)
 


Well the proof is in the real world, dex III does just fine in the transmissions it was put in. They can last a long time, and the issues they do have are unrelated.

Besides the tsb's are not very trustworthy anyway. Fixing valve cover leaks by installing spark plug wire retainers and removing heat shields? Blaming those two things are not the right way to go. Dex-cool antifreeze should have a ton of tsb's. It's way worse of a fluid than dex III could ever be considered.
 
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02NavyBlue said:
... The VI is the newer fluid and is partially synthetic which is iffy sometimes on older worn transmissions.
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May I ask were you got this info from? I'm not saying your wrong just looking for the right info.

91parkave said:
It's not a debate gm completely nixed the dex 3, put out multiple service bulletins etc..
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From what I can find on Google dexVI is a far better fluid but I'm not going to use it if dex III is safer for my tranny. BTW, my car has about 220XXXkm's and I'm also installing a shift kit, if that makes a difference. I've also noticed on the back of most jugs it says recommended for use in almost anything. I'm having a hard time finding just dex III in stores around here.

valvoline-maxlife-atf03_1.jpg
 
They pretty much stopped production on dex 3 cause 6,superceedes it. If you were to have your trans done at gm they would use dex 6 fluid not 3. Its compatible in all transmissions that used dex 3. And that's word from them. If someone claims they had a issue its probably because they never tried did any maintnence on their transmission till there's a problem. In which case it wouldn't matter how cheap or expensive the new fluid it will more than likely fail. If you look at specs of dex 6 compared to 3 you will see that its better able to handle heat and have a longer service life than 3.
 


91parkave said:
They pretty much stopped production on dex 3 cause 6,superceedes it. If you were to have your trans done at gm they would use dex 6 fluid not 3. Its compatible in all transmissions that used dex 3. And that's word from them. If someone claims they had a issue its probably because they never tried did any maintnence on their transmission till there's a problem. In which case it wouldn't matter how cheap or expensive the new fluid it will more than likely fail. If you look at specs of dex 6 compared to 3 you will see that its better able to handle heat and have a longer service life than 3.
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All of this is true. It is a fact though that dexron VI is better than Dexron III, just like synthetic motor oil is better than conventional motor oil. Both better fluids have better additives, both last longer, and both can take higher temperatures. There are reasons to use one or the other though. And when an older trans is rebuilt I would run dex VI as well since all of the seals are new and everything should be able to seal much better than worn out ones.

My trans is healthy-ish, with noticeable things different from how it would operate when new. I think a seal may not seal as well as it should somewhere along the way causing fluid pressure to drop slightly from when they were all new. Something's causing lower pressure when hot. (pcs replaced already) I don't think a better, "slipperier" fluid is going to do anything good for that issue, even with a trans with worn out clutches will slip more with a better engineered fluid. Heck even new dex III in a really worn out trans can kill it because the new dex III is better than 120k fluid.

At work we had a ford F150 5.4 (around 140K miles) come in for a misfire, it was a bad plug (called customer to confirm repair, and they requested a mobil 1 full syn oil change as well) and we replaced the plug and it ran really well with no noises. Then I got it in the air and did the oil change. After starting it the engine made lifter ticking, waited a while in case oil pressure had to build, but it never went away. And it didn't have a tick when it came in. We let it run in the lot for 20 minutes, and it was still just as loud. Just an example of how better fluids don't always agree with a worn engine/trans.
 
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In terms of Dex III vs the new stuff, the main difference I've noticed is viscosity at lower temps. Both fluids are pretty much identical in terms of viscosity at operating temperatures, but the newer Dex VI at cold temperatures is less thick and closer to operating viscosity than the old stuff. Probably some friction modifiers in there as well. I'd still stick with the older stuff on 97-03 transmissions, but I'll admit it's only because that's what I've heard people doing on here. I've got an 05 so it's all Dex VI for me. Any brand, transmission fluids between brands are almost identical compared to different brand motor oils.

And 02NavyBlue, to me it almost sounds like you have a worn line boost valve causing that pressure drop. If you can access the side cover and remove the channel plate and valve body, Sonnax makes a drop in replacement for the line boost valve and sleeve. The stock ones use a soft aluminum valve that wears away over time and becomes sloppy in the bore, leading to pressure drops. The Sonnax one apparently uses a hardened aluminum valve assembly, with more fluid channels cut to lubricate it better and make it last longer. I'm actually throwing one in myself once my damn valve body gaskets get here. OE Parts HQ, heard good things, but I ordered it last friday and I have yet to even receive a tracking number. If customer support doesn't respond soon, I'll be stopping by a dealership ASAP and telling OE Parts to eff themsel
 
nik12937 said:
And 02NavyBlue, to me it almost sounds like you have a worn line boost valve causing that pressure drop. If you can access the side cover and remove the channel plate and valve body, Sonnax makes a drop in replacement for the line boost valve and sleeve. The stock ones use a soft aluminum valve that wears away over time and becomes sloppy in the bore, leading to pressure drops. The Sonnax one apparently uses a hardened aluminum valve assembly, with more fluid channels cut to lubricate it better and make it last longer. I'm actually throwing one in myself once my damn valve body gaskets get here. OE Parts HQ, heard good things, but I ordered it last friday and I have yet to even receive a tracking number. If customer support doesn't respond soon, I'll be stopping by a dealership ASAP and telling OE Parts to eff themsel
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I had it all apart last fall to replace the 4th clutch hub, pcs, and tcc. Thought it was the pcs at fault but the shift kit is what made the real difference. I'd believe the boost valve idea, I've heard of those issues before and that they make a pressure booster too. So you have to separate the valve body from the channel plate? I've never done that before.
 
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If you remove the channel plate and valve body as an assembly like Bill shows in this thread: http://www.grandprixforums.net/threads/54448-How-to-transmission-4th-gear-side-cover-access

Then I believe you can set the assembly down on a table or something flat and remove the remaining bolts to separate the channel plate and valve body. The retaining pins hold the spacer plate and gaskets to the valve body portion, so I'd lift the valve body off the channel plate, ensuring the gasket stays in place while I flip it over so the mating surface faces up. The reason being that there are a bunch of check balls between the channel plate and valvebody, and done this way you won't have any falling out (hopefully). From there it's just a retaining clip like on the solenoids that hold the valve and sleeve in place.

Once my gaskets come in and I can finally get this done, I'll post an update with a few pictures to make it easier to understand.

I haven't actually opened that portion up yet, so this is all in theory, but from the advise I've gotten from Bill, his thread, and pictures in this thread here: http://pontiacbonnevilleclub.com/forum/viewtopic.php?f=8&t=1483 I'm pretty confident I know how this comes apart and goes back together now.

The pictures that helped most from that thread are on reassembly of the valve body. He placed the channel plate back on, and then the valve body which is why you see all his check balls "gooped" into place, but I believe reassembling the valvebody and channel plate off the car and reinstalling as one unit should allow me to avoid gooping them into place or having to worry about them falling out during reinstallation.

I hope that all made sense :D

Edit: I should add that I checked with Sonnax directly, and you can only use the revised boost valve and sleeve OR the pressure booster, they can't be used together. Being that you can raise line pressure in your tune, I'm personally using the revised valve and I'll have my line pressure raised when I get a tune from Overkill. Completely up to you though.
 


Yeah I had the channel plate sitting in the garage on the bench for a day just waiting on parts(thrust washers), wish I would have done it if I knew. That bonneville forum thread is really nice, I've been on it a few times here and there. Looks easy enough really, It's just digging all the way back in there again. I was planning on rebuilding my suspension this Saturday but if I'm going to do this fix I might as well do both at the same time.

Also you're saying the pressure booster is the same as the regular fix just modified for higher pressure? I just want my stock pressure back really. If I feel confident enough I'll go ahead and do it, that means new channel plate gaskets (again), valve body gaskets and spacer plate, and the sonnax boost valve.
 
I actually emailed triple edge performance asking him if I should run dex 3 or dex 6 on my car and my brothers car. At the time my brothers 03 had 50K miles and mine was sitting around 80K miles. He told me to run dex 3 since the cars had high mileage. So I have stuck with dex 3. Some have complained about the trans slipping with dex 6.
 
02NavyBlue said:
...The VI is the newer fluid and is partially synthetic which is iffy sometimes on older worn transmissions.
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91parkave said:
It's not a debate gm completely nixed the dex 3, put out multiple service bulletins etc..
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The Guz said:
I actually emailed triple edge performance asking him if I should run dex 3 or dex 6 on my car and my brothers car. At the time my brothers 03 had 50K miles and mine was sitting around 80K miles. He told me to run dex 3 since the cars had high mileage. So I have stuck with dex 3. Some have complained about the trans slipping with dex 6.
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Wow, this just keeps going back and forth. I was gonna buy dex VI but now in not so sure.
 
02NavyBlue said:
Yeah I had the channel plate sitting in the garage on the bench for a day just waiting on parts(thrust washers), wish I would have done it if I knew. That bonneville forum thread is really nice, I've been on it a few times here and there. Looks easy enough really, It's just digging all the way back in there again. I was planning on rebuilding my suspension this Saturday but if I'm going to do this fix I might as well do both at the same time.

Also you're saying the pressure booster is the same as the regular fix just modified for higher pressure? I just want my stock pressure back really. If I feel confident enough I'll go ahead and do it, that means new channel plate gaskets (again), valve body gaskets and spacer plate, and the sonnax boost valve.
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The pressure booster uses the stock sleeve, but replaces the inner line boost valve and reverse boost valve, as well as uses a higher pressure spring. The updated or fix valve includes a new sleeve with more fluid channels, and new line boost and reverse boost valves that are hardened aluminum and have extra fluid channels cut in them too. That fix uses the stock spring. So they are actually a bit different. I could see the pressure booster wearing over time like the stock valve, so in your case I'd also use the fully updated design and leave boosting line pressure to a tune if you want in the future. I can't really see a purpose to the pressure booster to be honest, just seems like extra work when tuning accomplishes the same thing.


A lot of the problems people experience with Dex VI has to do with synthetic fluids (even partially synthetic like Dex VI) not coping as well with larger tolerances. For an 04+ I'd always use Dex VI, but with a 97-03 I'd only use it if the transmission was taken care of and hasn't been driven hard. I'm not sure if anyone can pinpoint exactly why people have problems with Dex VI, since some people are fine and others get slipping issues.

If I had a 97-03 model, what I would personally do is go ahead and do a pan drop and add the Dex VI. I'd drive it nice and easy for a week or two, maybe give it one or two WOT runs at maximum, and see if I notice any slipping. If not I'd keep it, and if I did notice slipping I'd just do another pan drop and switch back to Dex III before any actual damage or excessive wear is created.

Just as a side note, never use any of that Lucas crap either. Even in engines, but especially not transmissions. Does it work? To an extent, but it's a band-aid fix and in the long run will cause fluids to stick in places too long/not get cycled through as often. My buddy uses it in his Cadillac and it does prevent knock on startup, but it's causing some nasty build up under his valve covers. So sort of helping one problem while creating another. I don't want to think of the buildup it causes in a transmission, including heat buildup since the fluid isn't really circulating as well as it normally should.
 
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