4t65e which ATF?

[nascarnation]

Dex VI is a GM fuel economy deal.
Dex III equivalents are better for durability (syns if you run hot).
Allison TES-295 is probably the most rigorous spec, that stuff was developed for trash trucks and city buses, two of the most demanding vocations.

 

[SoNic67]

Originally Posted By: 901Memphis

They hard shift because of worn clutches tripping the max adapt mode because shift times are too long. DexronVI won't affect this.

The low pressure is the cause why the shift times take forever. But sure, the "cool" thing around here I see is to recommend LV synthetics (Dexron VI is the same as Mercon LV) with no regard to the actual application requirements.
The 100C viscosity on LV specs is only 6 cTs, versus around 8 cTs for the normal ATF. The fact that it "works" in some transmissions doesn't mean that it will for everyone.

 

[Blinker]

Originally Posted By: 901Memphis
Originally Posted By: SoNic67
I would NOT use a Low Viscosity formulation in that transmission, especially when it's already hard shifting. Unless you want to put it out of it's misery quicker...
All the synthetic formulations are LV, exception being Mobil 1 and Amsoil (they have both variants). They create less operating pressure than the conventional fluids, and with the worn transmission pump, pressure it will be even lower.
That's why the shifts hard when the transmission heats up - the fluid becomes thinner. Probably the additives are depleted, so it's viscosity drops very low.

For that transmission the best you can get now is Castrol HM. The drain and refill needed to be done at every 30-40K miles. If the fluid comes out grey, do again a drain and refill after some 200 miles.


They hard shift because of worn clutches tripping the max adapt mode because shift times are too long. DexronVI won't affect this.

I would use the Supertech DexronVI which is the same as the name brand.


Not trying to come off rude or anything but wasn't your 4T65e rebuilt? If it was then sure, go ahead and use Dexron vi since everything was assembled back to spec. That's what I would recommend in your situation.

Now on an original tranny with some miles on it that is exhibiting problems I for the life of me cannot figure out why a thinner fluid would be recommended.

IME, and for MANY others (visit some dedicated GM FWD vehicle forums) Dexron vi can cause issues in older transmissions. Switch back to a dexron III equivalent or a high mileage atf and the issue is gone. VISCOSITY is key here. Some of these older units just flat out need higher viscosity.


It doesn't matter how shear resistant dexron VI is. If the starting viscosity is too low for the tranny to operate correctly then it is the wrong fluid. Period. Use a higher viscosity atf and change it out every 30,000 miles and viscosity shouldn't be an issue.

I feel like this is common sense.

 

[Lubener]

If your transmission has shifting issues with the dex6, the transmission likely is on its last leg anyways.Dex 6 is claimed to have much more stable viscosity over all temperature ranges and shear resistance over it service life. I have used it in my 4T60E and have no issues at all.

 

[901Memphis]

The transmissions have no issues with the lower viscosity, they actually prefer it from my experience. Plenty of people using DexronVI and Maxlife in the 4t65e and people even drag racing with these fluids.

The biggest issue with the 4t65e has been clutch wear causing max adapt which is a command for maximum line pressure! This is a frictional matter not viscosity related issue.

 

[901Memphis]

Originally Posted By: nascarnation
Dex VI is a GM fuel economy deal.
Dex III equivalents are better for durability (syns if you run hot).
Allison TES-295 is probably the most rigorous spec, that stuff was developed for trash trucks and city buses, two of the most demanding vocations.


TES-295 fluids are basically the only way you can get what a DexronIIIH fluid should be, without gambling in a dex/merc fluid, so I have no problem recommending TES-295 although the cost and availability is a factor depending on location.

 

[CocoNut808]

Update:

Shift kit, magnets, trans filter, and dex III fluid installed.

so far trans shifts as it should. will drive a few thousand more miles then switch fluid to Maxlife.

 

[JustN89]

Originally Posted By: CocoNut808
Update:

Shift kit, magnets, trans filter, and dex III fluid installed.

so far trans shifts as it should. will drive a few thousand more miles then switch fluid to Maxlife.

Too bad I missed this thread. I had the same problem just a few months ago in my 05 Impala with the 4T65E. I did the exact same thing: shift kit, magnets and trans filter, only I went with Maxlife. So far, it shifts better than it ever has. It's been about 1,000 miles since then (it's a commuter car - gets my wife to and from work). If you plan on doing frequent pan drops, I'd recommend a Dorman pan as it comes with a drain bolt. Quality seems hit or miss depending on where you read, but so far our hasn't leaked at all and has held up pretty well. Best of luck!

 

[leox]

Hi guys

Very glad I found this thread - I have the Volvo XC90 T6 with 4t65 tranny - previous owner had the misfortune of rebuilding it at 75K miles - and I bought it at 80K. ATF is still clean pink, but it's been almost 2 years (albeit just 5K millage) - and I'm contemplating of doing a ATF drain/fill.

But in the UK, Valvoline Maxlife is not widely sold (or extremely expensive in 1 litre bottles) - the only options I could find is Castrol Dex III (which is also only available in 1 litre), or Mannol (German brand) multivehicle ATF (which lists GM Dex III D as one of the many vehicles this supposedly fits) - available in 10 or 20 litre barrels.

I wonder if anyone had experience with using Mannol multivehicle ATF in 4T65e?

Thanks in advance!
Namo Amituofo

 

[das_peikko]

It's supposed to be Dexron III. But now they're listing it as Dexron VI / Mercon LV which is confusing to people including myself.

 

[dave1251]

Originally Posted by SoNic67
I would NOT use a Low Viscosity formulation in that transmission, especially when it's already hard shifting. Unless you want to put it out of it's misery quicker...
All the synthetic formulations are LV, exception being Mobil 1 and Amsoil (they have both variants). They create less operating pressure than the conventional fluids, and with the worn transmission pump, pressure it will be even lower.
That's why the shifts hard when the transmission heats up - the fluid becomes thinner. Probably the additives are depleted, so it's viscosity drops very low.

For that transmission the best you can get now is Castrol HM. The drain and refill needed to be done at every 30-40K miles. If the fluid comes out grey, do again a drain and refill after some 200 miles.



It would be nice if this post had some factual information like a DEXRON VI is actually thicker throughout the lifetime of the fluid compared to a DEXRON III how long has this fact been known a decade?

 

[dave1251]

Originally Posted by leox
Hi guys

Very glad I found this thread - I have the Volvo XC90 T6 with 4t65 tranny - previous owner had the misfortune of rebuilding it at 75K miles - and I bought it at 80K. ATF is still clean pink, but it's been almost 2 years (albeit just 5K millage) - and I'm contemplating of doing a ATF drain/fill.

But in the UK, Valvoline Maxlife is not widely sold (or extremely expensive in 1 litre bottles) - the only options I could find is Castrol Dex III (which is also only available in 1 litre), or Mannol (German brand) multivehicle ATF (which lists GM Dex III D as one of the many vehicles this supposedly fits) - available in 10 or 20 litre barrels.

I wonder if anyone had experience with using Mannol multivehicle ATF in 4T65e?

Thanks in advance!
Namo Amituofo



Is there a DEXRON VI licensed product available?

 

[Silverado12]

Originally Posted by SumpChump
We had a hot slam banging 4t65e and when I called the tranny shop he instantly replied... "Those are my bread n butter". No kidding. I hated that transmission.

He said they put in a shift kit and add a cooler and they go for 30-60k more, if they had been slamming already. If done preemptively.... then he said it would go several hundred k miles.

I've heard of those problems when I had my Impala, so I did fluid and filter changes every 25K miles. Never had an issue with mine and all I used was NAPA brand Dex III.