dex 3 to dex 6 on 14k Buick

[carviewsonic]

I'm going to change transmission fluid from dex 3 to dex 6 (and filter) on my 14k '05 Park Ave. I'll do a second change at the next oil change, which is about 3k from now. That will have it at close to 80% dex 6. Reasons are: To get break-in debris out, which I believe would be beneficial; To switch over to dex 6, which is supposed to be superior to dex 3. I don't want to fiddle with the cooler lines, which is why I'll just drop the pan twice.
I'm a bit paranoid now about the 4t65e since my other Park Ave ('03) with 160k is having transmission issues. Looks like the '05 garage queen is going to be our daily driver, and the '03, I don't know what to do with that one. Rebuild with installation runs about $3200 here in Alberta, more than the car is worth.

 

[The_Jeff]

ok

 

[SoNic67]

So you gonna switch from an ATF with viscosity at hot of 7.2-7.4 cSt to one that has 5.4-6 cSt, just because some people told you that "it's better"?
The Dex VI is formulated for newer design Low Viscosity transmissions (fuel economy). Dropping it into older design transmissions designed for Dex III is wrong (will create a lower working pressure with existing pump).
I would use either Castrol Merc/Dex (7.2 cSt) with LubeGard Red, or Castrol High Mileage (8 cSt). Or, if you are into Mobil 1 use their Synthetic ATF, it has 7.4 cST. Don't even look at other "synthetics", they are almost all LV.

 

[slacktide_bitog]

Originally Posted By: SoNic67
The Dex VI is formulated for newer design Low Viscosity transmissions (fuel economy). Dropping it into older design transmissions designed for Dex III is wrong


Dexron-VI is fully backwards-compatible to all GM automatic transmissions

 

[SoNic67]

Sure it is, don't mind the facts and numbers that I just posted above, they are just distractions. That's why California has a law exactly against that miss-representation.
Read this at the end: http://content.valvoline.com/pdf/maxlife_atf.pdf
"*Please note that legislation in California prohibits Valvoline from recommending MaxLife ATF in certain applications
where the viscometrics of MaxLife ATF do not match those of the official OEM specification. Valvoline therefore does not
recommend the use of MaxLife ATF in these applications in California."

 

[HangFire]

Originally Posted By: SoNic67
So you gonna switch from an ATF with viscosity at hot of 7.2-7.4 cSt to one that has 5.4-6 cSt, just because some people told you that "it's better"?
The Dex VI is formulated for newer design Low Viscosity transmissions (fuel economy). Dropping it into older design transmissions designed for Dex III is wrong (will create a lower working pressure with existing pump).
I would use either Castrol Merc/Dex (7.2 cSt) with LubeGard Red, or Castrol High Mileage (8 cSt).


This ignores the fact that the older mineral-based (read your links) conventional ATF's shear down quickly, and the newer synthetic or synthetic blend ATF's maintain their viscosity better.

Since we're on a Castrol kick, the synthetic ATF link:
http://catalog.parentpetroleum.com/Asset/Castrol Transmax FS MV ATF.pdf

And "some people" would be GM.

 

[SoNic67]

"Shear down quickly" it's a myth. That's why the factory recommended refill intervals are around 80-100k miles for normal use. Drain and refill at 35k and you are golden.
Of course GM would love to sell you another car as quickly as possible. They care only to last trough the warranty.

 

[901Memphis]

Mineral DexronIII is probably already sheared less than the viscosity of DexronVI.

DexronVI is the correct fluid for this transmission and Maxlife Dex/Merc is even better if you don't mind using non oem fluids.

If you want to stay ahead of the problems with these transmissions, you can install the transgo shift kit which will help pro long the clutches longer.

Also be careful with which transmission filter you buy, most are made in the China now with poor fitment, the two best choices are allomatic from triple edge website or the filter that Napa has usually is allomatic or at least the Filtran made in China which is the best from that country.

 

[HangFire]

Originally Posted By: carviewsonic
I'm a bit paranoid now about the 4t65e since my other Park Ave ('03) with 160k is having transmission issues. Looks like the '05 garage queen is going to be our daily driver, and the '03, I don't know what to do with that one. Rebuild with installation runs about $3200 here in Alberta, more than the car is worth.


Your '03 is a prime candidate for a low mileage scrapyard transmission. Since you have time, shop around, sometimes a non-local deal plus shipping is less than local. Some can be had with a 30, 45, 60, or 90 day warranty.

 

[HangFire]

Originally Posted By: SoNic67
Drain and refill at 35k and you are golden.


On that we can agree on. Use a quality DexronIII compatible product and drain and fill at regular intervals, and you'll get all you can get out of an old transmission.

One thing about old GM products, there are so many on the road, there are always solutions available for any common problem they have. The OP might do well to start a thread "what to do about my 03 transmission" or somesuch.

 

[901Memphis]

My Buick Century has the same transmission as the park ave, and currently has a proper rebuild done by triple edge in it but prior to that it banged gears in max adapt mode for two plus years and was still working when replaced, so I wouldn't jump to replace the transmission until it absolutely needs it.

 

[SatinSilver]

Originally Posted By: 901Memphis
My Buick Century has the same transmission as the park ave, and currently has a proper rebuild done by triple edge in it but prior to that it banged gears in max adapt mode for two plus years and was still working when replaced, so I wouldn't jump to replace the transmission until it absolutely needs it.


How much did that cost from Triple Edge if you don't mind me asking?

 

[Lubener]

Originally Posted By: SoNic67
So you gonna switch from an ATF with viscosity at hot of 7.2-7.4 cSt to one that has 5.4-6 cSt, just because some people told you that "it's better"?
The Dex VI is formulated for newer design Low Viscosity transmissions (fuel economy). Dropping it into older design transmissions designed for Dex III is wrong (will create a lower working pressure with existing pump).
I would use either Castrol Merc/Dex (7.2 cSt) with LubeGard Red, or Castrol High Mileage (8 cSt). Or, if you are into Mobil 1 use their Synthetic ATF, it has 7.4 cST. Don't even look at other "synthetics", they are almost all LV.


Pure nonsense. Go with the dex 6 in your 05.Why listen to someone who put dex 6 in a dying transmission and had an issue.I have DEX 6 in an older 4T60E and it shifts like a gem. The only good advice I read is using Lubeguard Red.

 

[RichardS]

I have the same transmission in a century, with 107k miles currently. I changed the fluid (3 pump and fills a week apart) at 106k miles with Castrol Transmax high mileage. Finished off with Lubegard Red, and haven't had any issues yet.

A few times, previous to the change, It'd occasionally end up in max adapt when the fluid was up to temp after 15-20 city driving.

Off topic: It seems like you very much enjoy your Park Avvenue, so instead of viewing the repair as exceeding the resale value of the car, and just look at it as a 90% discount off a new car.

 

[Fsharp]

If you're choosing between Supertech dex 6 or III then I'd get the 6, but if you're willing to pay for a regular viscosity synthetic that is Dex III compatible you might as well get one of those and not have to worry about too low of viscosity.

 

[carviewsonic]

Thanks everyone for your input, you have given me a few things to mull over tonight. I don't bring up subjects like this at work... eyes would glaze over instantly

 

[zeng]

Originally Posted By: SoNic67
So you gonna switch from an ATF with viscosity at hot of 7.2-7.4 cSt to one that has 5.4-6 cSt, just because some people told you that "it's better"?
The Dex VI is formulated for newer design Low Viscosity transmissions (fuel economy). Dropping it into older design transmissions designed for Dex III is wrong (will create a lower working pressure with existing pump).
I would use either Castrol Merc/Dex (7.2 cSt) with LubeGard Red, or Castrol High Mileage (8 cSt). Or, if you are into Mobil 1 use their Synthetic ATF, it has 7.4 cST. Don't even look at other "synthetics", they are almost all LV.

+1
At 30k drain/fill, it probably provides higher operating viscosity(and hence components protection) against a Dex VI.

 

[69GTX]

Ford's Mercon V is essentially a semi-synthetic DEX III with a stronger add pack. It's been around since about 2000. My 2002 Lincoln trans calls for Merc V. No way I put the Valvoline ATF-LV in there. While regular conventional Dex 3 probably shears down by 40% during the recommended OCI, the Merc V only shears down by approx 19% which still keeps it above the Valvoline MaxLife visc of 5.8 even after 30K miles. The MaxLife supposedly shears down by 3% or less. Synthetic ATF Dex 3's like Mobil 1 ATF start out around 7.5 cSt and stay above 6.8 for an OCI (approx 3-10% shear rate). Plenty of options without resorting to a 5.8 cSt starting viscosity for a transmission that specced 7.0-7.5 to begin with.

 

[i_hate_autofraud]

I’m a 4T65E owner too! It’s not much fun yet.

If you drop the pan and change the filter, I’d stack in a few extra magnets to pick up wear metals, they cause secondary wear by circulating and the EPC and shift solenoids pick up the particles and start to stick causing more shift issues.

Watch, though, the pan is zero clearance and there’s only a few spots with enough room to allow extra magnets.

There’s a GM TSB that admits the earlier square magnet they had on some cars was ineffective and to change to a large ring magnet. You need more then that to make a difference thou.

Search “ 4T65E magnet” etc, to get the TSB.

Also here’s a PDF that lists upgrade parts from Sonnax, etc, that fix chronic 4T65E problems for future reference. Some can be used without a teardown.


GM 4T65-E TRANSMISSION UPGRADE PARTS
https://app.box.com/s/drsf61akkxu6bw2a2qcnl1ajuhgkh9hx

 

[901Memphis]

Originally Posted By: SatinSilver

How much did that cost from Triple Edge if you don't mind me asking?


The standard rebuild is $1750+freight shipping and core charge, plus I had to pay an Indy mechanic for installation.

You are at a low mileage so I you don't need a new transmission if you get ahead of the known problems with the transgo shift kit and there are some sonnax parts which are a good idea to install too. Just look at what they put into the rebuild and you can see what you need that is easy to install without tearing into it. The transgo kit includes accumulator Springs which will greatly help the clutches over the life of the transmission as well as improved shift feel.


Triple edge 4T65e standard rebuild link