is Dexron VI preferred for a 2000 Malibu 4T40-E

[LScowboy]

have a 2000 Malibu with 4T40-E transmission (3.1 engine) with 155K miles and I believe it calls for Dexron III - I am doing a pan drop, and changing the filter out with new GM filter, and changing out the oil feed manifold proactively, as these are known to break around 150K miles.

Is it OK to use Dexron VI without a full flush? - I don't like to change ALL of the fluid in an older transmission that has not been serviced before, that usually doesn't end well.

 

[Oro_O]

It's not the changing the fluid "all at once" that's the problem. It's the "power flush" some quick lubes do. If you do it yourself without pressure, no worries.

I use a Dex VI rated (Valvoline MaxLife) in a 4L30-E. It loves it. It whined and hesitated occasionally before. Flushed fully (I have an atf cooler so easy to disconnect and pump out) and changed - now it runs like new and has for 20k since then. Or do a drain/fill now, another in a few months. That will get you to 75% new fluid on that transmission, I believe (it does on the 4L30-E). It is compatible with what is in there assuming it's Dexron rated of some sort.

 

[SteveSRT8]

Please note that there are no "powered flush" machines, at least none that can be located.

All transmission fluid exchange machines are passive and use your trans' pump to do all the work. NOTHING is 'forced' anywhere, and all fluid follows the exact same paths it does during normal operation.

Fluid exchanges are never a substitute for a pan drop and filter change especially when the trans is young as most units generate the majority of debris early in their life cycle.

Valve bodies are full of hydraulic check valves to force fluid to flow only one way without reversion, so no powered flush could do much anyway...

 

[Oil Changer]

Has it ever been changed in the past? If the answer is no, leave it. You're begging for trouble. No offense but it's an '00 Malibu and the holiday.

Flush your brake fluid instead.

 

[Oro_O]

Originally Posted By: SteveSRT8
Please note that there are no "powered flush" machines, at least none that can be located.


I was able to find 11 within 5 miles of my zip code using the manufacturer's database. They are out there. Just do a little homework. The machines can run in passive mode, or in powered mode w/compressed air. At least the BG machines. There's a reason they are called a "power flush" machine. So yep, they can be located...

 

[SteveSRT8]

Originally Posted By: Or
Originally Posted By: SteveSRT8
Please note that there are no "powered flush" machines, at least none that can be located.


I was able to find 11 within 5 miles of my zip code using the manufacturer's database. They are out there. Just do a little homework. The machines can run in passive mode, or in powered mode w/compressed air. At least the BG machines. There's a reason they are called a "power flush" machine. So yep, they can be located...



I owned a B&G machine! It was completely passive, just a bladder and a tank with a tray full of adapters. I have personally stopped in at dozens of shops all along the West Coast of Fl during my extensive travels for business and I have yet to see any shop either new or old with anything else.

The only powered machines were simple pumps that worked through the dipstick hole. Not a single forced flusher in the bunch.

 

[Trav]

Don't bother with this drain and fill business, its a waste of time and money. If the transmission is bad its bad if its good and you are doing it as maintenance its no problem.

I run into this on a regular basis, the customer notices the tranny is not working like it use to, its slipping, shifting funny, taking a long time to engage, etc.
At this point the pooch has already been screwed, it doesn't matter if you do drain and fills the tranny is very possibly damaged and any method used will be blamed for damaging the tranny.

Doing the line off method uses the units own pump to exchange all the fluid and is perfectly safe when done properly.
Using a machine in powered mode (i have not seen one, only heard) or unpowered mode simply means engine on or engine off, it does not back flush the fluid in either mode.

Like i said i you are doing this as preventive maintenance why would anyone want to pay for 30+qts of fluid to change 12?
Do it right and get it done with one job. If the want to know how to do this properly just ask.
Dex VI is the correct fluid for this unit.

 

[The_Eric]

Originally Posted By: LScowboy
have a 2000 Malibu with 4T40-E transmission (3.1 engine) with 155K miles and I believe it calls for Dexron III - I am doing a pan drop, and changing the filter out with new GM filter, and changing out the oil feed manifold proactively, as these are known to break around 150K miles.

Is it OK to use Dexron VI without a full flush? - I don't like to change ALL of the fluid in an older transmission that has not been serviced before, that usually doesn't end well.


Sure it does. Happens nearly every time I service a customer's transmission. Lots of neglected transmissions out there and I treat them all the same.




Originally Posted By: Trav
Don't bother with this drain and fill business, its a waste of time and money. If the transmission is bad its bad if its good and you are doing it as maintenance its no problem.

I run into this on a regular basis, the customer notices the tranny is not working like it use to, its slipping, shifting funny, taking a long time to engage, etc.
At this point the pooch has already been screwed, it doesn't matter if you do drain and fills the tranny is very possibly damaged and any method used will be blamed for damaging the tranny.

Doing the line off method uses the units own pump to exchange all the fluid and is perfectly safe when done properly.
Using a machine in powered mode (i have not seen one, only heard) or unpowered mode simply means engine on or engine off, it does not back flush the fluid in either mode.

Like i said i you are doing this as preventive maintenance why would anyone want to pay for 30+qts of fluid to change 12?
Do it right and get it done with one job. If the want to know how to do this properly just ask.
Dex VI is the correct fluid for this unit.




You've hit all the right points.


O/P- if it matters to you, I've got a '98 Malibu with the 4T40E that may or may not have been serviced when I got it at with 172k miles. It got Dex VI and works just dandy.

 

[simple_gifts]

The OP didn't indicate he was having problems with the transmission; he is just doing a fluid change.

 

[LScowboy]

Originally Posted By: simple_gifts
The OP didn't indicate he was having problems with the transmission; he is just doing a fluid change.

exactly - I have to do this filter change anyway, and I especially have to change this transmission oil feed 4-pipe manifold that is notorious for breaking on this model.

I know a fair amount about transmissions, and I know that changing ALL of the fluid on a transmission that has never had fluid changes is a recipe for problems.


what I want to know is:

is Dexron VI OK for this transmission - what year did they change over to it on this tranny?

is the fact that just by doing drain and fill, about 40% of the old (Dexron III) will be left in there and mix with the Dexron VI gonna be an issue?

I am a firm believer in leaving some of the old fluid in so as not to "shock" the tranny into premature failure, but not sure about these two blending nicely (old Dexron III at perhaps 40% and new Dexron VI at perhaps 60%)

 

[stevejones]

DexVI is totally backwards compatible. I have it in both my 4L60e trannies from the '90s...

 

[Trav]

Originally Posted By: LScowboy
I know a fair amount about transmissions, and I know that changing ALL of the fluid on a transmission that has never had fluid changes is a recipe for problems.

Originally Posted By: LScowboy
I am a firm believer in leaving some of the old fluid in so as not to "shock" the tranny into premature failure,

really?

No offense but i guess we should just change a couple of qts out each oil change so we don't shock the engine either.
Believe whatever you want (its not my transmission) but these are just myths with no basis in fact.
Every transmission failure i have seen right (or shorty after) after a fluid change has been installer error. Either they damaged the filter seal/o ring, used the wrong filter (common on some models that use different pan depths on the same model unit) or used the wrong fluid.
You cannot shock a transmission into failure premature or otherwise with new fluid. If its going to fail it will fail regardless of percentage changed at once.

Yes Dex VI is compatible with Dex III.

 

[147_Grain]

Originally Posted By: Trav

You cannot shock a transmission into failure premature or otherwise with new fluid. If its going to fail it will fail regardless of percentage changed at once.

Well said! Transmissions that fail after servicing only do so from the use of inferior products, mechanical error, or they were already on their last leg due to lack of maintenance over the years.

 

[Bgallagher]

I would do a pan drop and fill with Maxlife. You should drain about 7 qts and it is roughly a 12 qt system. A flush shouldn't be necessary.

 

[LScowboy]

So perhaps some of you geniuses who are sitting back sounding all authoritative would like to explain why such a high percentage of transmissions that have never been serviced, then suddenly have all of the fluid changed or flushed at 150K, suddenly have issues within a month or three.

I used to think that this was urban legend as well, until I worked in a transmission shop for several years.

I don't know if the detergents in the fresh fluid are breaking free some pent-up debris that is clogging passages or what, but when the new fluid is introduced in stages, like changing 25% at a time, for example, like every few months over the course of a year or two, this premature failure is not seen. Perhaps logically it doesn't make sense to you, but it is happening just the same, seen hundreds of cases of this.

 

[MolaKule]

I work with three transmssion shops who work with me to test new transmission fluids and they tell me they have not seen transmission failures after introducing new fluid.

Like 147_Grain and others have said, if it was going bad it's gonna go bad, mostly due to not changing out the fluid and keeping it and the filter clean.

Transmissions need love and periodic fluid changes as well; it's called "Preventive Maintenance."

 

[LScowboy]

yes, but if that transmission has not gotten "the love and periodic fluid changes" throughout its life, you bring it to a quick demise by changing all of the fluid all at once. And I would be worried about a transmission shop that is not well aware of this!

I know you are a respected transmission fluid guru here, and it pains me that you are unaware of this phenomenon. Maybe ask a few more transmission builders? - This is fairly well known.

Sure, that neglected transmission may only have another 3 years left in it, but no reason to blow it up in a month when the new fluid could be introduced slowly over a year or so.

 

[Trav]

Hundreds of cases? I guess i must be one of the lucky ones for the last 42 years of doing this professionally.
I might not be a genius but i know dex VI is compatible with dex III. Nuff said. LOL

 

[Trav]

After thinking about this i have some thoughts.
Assuming its true that you have seen a lot of failures and i have seen none what is the reason for the discrepancy?
I don't use a machine, only exchange the fluid in the direction of flow but only after changing the filter and cleaning the pan first.

I remove the drain plug and the pan then replace the filter before going any further or if no plug is present i remove the return line and pump about 4 qts out then drop the pan.
Once the pan is spotless and the filter is replaced i fill the unit and continue with the line off for 4 more qts repeating until the fluid is the same color coming out is the same as whats going in.
I never use flushing chemicals, LG or BG sure but never the flush.

Using a machine without dropping the pan, cleaning it and replacing the filter first would quite possibly circulate some junk which would be undesirable.

 

[SteveSRT8]

Originally Posted By: 147_Grain
Originally Posted By: Trav

You cannot shock a transmission into failure premature or otherwise with new fluid. If its going to fail it will fail regardless of percentage changed at once.

Well said! Transmissions that fail after servicing only do so from the use of inferior products, mechanical error, or they were already on their last leg due to lack of maintenance over the years.


Absolutely true and validated by my 40+ years of fleet ownership, transmissions do not die simply from new fluid.

it's a myth...