Looking for 4t65e advice

[easymachtdas]

Hello,

after spending hours researching, I decided to make a new post asking about Dexron 3 vs dexron 6.

I just did a drain and fill on a 2007 Uplander that has a 4T65e (M15) transmission. I ended up using Supertech high mileage dexron 3 fluid. I understand dexron 6 is recommended for this year model, and am curious how detrimental the mismatch of fluid is. As I understand after reading through the internet, dex 6 is a lower viscosity fluid, which matters a lot more for newer gm autotrans with 6 gears.

Any input is welcome. I guess my main question is whether or not i need to drain this dex 3 asap and replace it with dex 6. Considering its an older transmission I am hoping there is no harm using dex 3.

 

[Lubener]

Dex 6 is the replacement to Dex 3 and is backward compatible with transmissions that originally spec'd Dex 3. I don't believe there is a detriment using Dex 3 in your 4T65E as I believe that is what your transmission originally came with. The Dex 6 is more shear stable as miles are accrued on the fluid than Dex 3, so Dex 3 won't last as long as Dex 6. Some people use Maxlife with good results but I have no experience with it. My personal experience with Dex 6, I noticed harsher shifts with my 4T65E transmission when hot ( Probably due to the lower viscosity ) after switching to DEX 6.

 

[slacktide_bitog]

You do not need to drain it asap, but Dexron VI is better. Just replace it when convenient.

Also, if your transmission doesn't have a drain plug, get an aftermarket pan that has one. It will make future ATF changes much easier

 

[Trav]

Other than a hardened 4th gear input shaft and a few minor modifications the 4T65E is the same old unit that spec'd dex III, in these and other dex III transmissions I use a TES-295 fluid (I use Mobil Delvac 1 ATF), it stays in grade and provides really nice shifts. Not cheap but due to its stability has a longer change interval. Amsoil ATF (not the fuel efficient ATL) works very well and also has a long life.

https://www.mobil.com/en/lubricants/for-businesses/heavy-duty-lubricants/products/mobil-delvac-1-atf

 

[easymachtdas]

Other than a hardened 4th gear input shaft and a few minor modifications the 4T65E is the same old unit that spec'd dex III, in these and other dex III transmissions I use a TES-295 fluid (I use Mobil Delvac 1 ATF), it stays in grade and provides really nice shifts. Not cheap but due to its stability has a longer change interval. Amsoil ATF (not the fuel efficient ATL) works very well and also has a long life.

https://www.mobil.com/en/lubricants/for-businesses/heavy-duty-lubricants/products/mobil-delvac-1-atf

this is great info, thank you. I was wondering what upgrades were implemented!

Thank you everyone for the insight shared

 

[wlk]

I did 2- 2gal drain and fills in my 07 Impala with Maxlife and it's been fine. Will probably go with Valvoline Extended Protection ATF next time as it's a higher visc than Maxlife.

 

[HyundaiAbuser]

I tried all sorts of atf in my 2007 impala 4t65e working on a 3-4 shift flare. Really they all worked well and not much difference to be had with any of them and I drove the wheels off that thing in the years I had it. To list them
Maxlife (including cvt compatible versions
Castrol universal atf/cvt
Amsoil non fuel efficient
Valvoline dex/merc
Castrol import multi vehicle
One of the tes 295 fluids I don’t recall which

Essentially they all worked the exact same for me and in your shoes I’d pick a tes-295, higher viscosity amsoil or hpl to not have that what if there’s something better feeling.

 

[VolvoZ]

Looking for advice from the BITOG 4T65E transmission experts. (Perhaps @clinebarger could chime in). In the yellow highlighted area of the photo(lower right), the tube where it inserts into the cover is able to move approximately 1/8” corresponding to the arrows (it is not a tight fit). Is that normal to be somewhat loose? If not normal, what issues could this cause and what can be done to fix the looseness ?

For some background, this transmission (in an ‘05 Buick LeSabre w/100K miles) did have a TransGo shift kit installed a few years back. Shifts great except for an occasional “goes into neutral then bangs into first gear” behavior when stopping fairly quickly, then accelerating. That behavior seems to be more prevalent when stopping at an uphill stop. Thanks!

 

[clinebarger]

That's the Manual 2/1 Brake Band Servo Feed Pipe, Gives engine braking in 1st & 2nd gears. Will not cause any shifting issues & it's common for the pipe to fit loose in the servo housing.

The neutraling out is likely the Input Clutch Piston is worn.

 

[VolvoZ]

Thank you much!