4L80E. Any Recommendations? Dex VI?

[Smith5361]

Have a 4L80E in my 1997 truck. Truck is fairly large and has some minor engine work done to the big block. Transmission has a larger cooler installed, Mag Hytec Pan that holds about 3 extra quarts, and a Transgo HD2 shift kit. Truck has 93k on it.

Ive changed the tranny fluid ancouple times via pan drop. Most recently was about 3k miles ago when the new pan and larger cooler was installed. This time I installed the new pan, filled it up, and then flushed about a gallon through the cooler line out before hooking every thing up and refilling back to spec. This time I used Valvoline Max Life Dex VI.

The transmission has always shifted fine and had firm shifts, especially with the shift kit installed, but once the truck for a while, ive always notice the shifts get a little less firm, still good just seems like its a little different. Has been like this as long as i can remember. Could be ancomputer thing, who knows.

Anyway with that background info is there anything else you guys would suggest? Was VI a bad idea? Should i try to find some Dex III equivalent to put in? I see so much contradictory info on if the Dex VI shoukd of been installed in a Dex III transmission. Basically that viscosity levels are different even though VI is backwards compatible etc. Whats the real answer. Also I see many people talk about Red Lubeguard. Should i throw some of that in for good measure?

Thanks

 

[The_Cams]

I've always been more comfortable with Mobil1 Syn ATF for trannies calling for Dex III. I went with Mobil1 ATF in a 4T60E and it ran great. A bit thicker than Dex VI or Maxlife ATF.

 

[zeng]

Consider ATF+4 .

 

[kschachn]

Originally Posted by Smith5361
Anyway with that background info is there anything else you guys would suggest? Was VI a bad idea? Should i try to find some Dex III equivalent to put in? I see so much contradictory info on if the Dex VI shoukd of been installed in a Dex III transmission. Basically that viscosity levels are different even though VI is backwards compatible etc. Whats the real answer. Also I see many people talk about Red Lubeguard. Should i throw some of that in for good measure?

Thanks

This question comes up a lot on here for some reason, the real answer is that dexron VI is the correct and licensed replacement for dexron III. The viscosity is different yes, but only to begin with. dexron VI is required to be more shear stable than dexron III so after a short period of operation the viscosity level is the same or close between the two. Licensed dexron VI fluids are superior to the old dexron III any way you look at it.

 

[Snagglefoot]

+ 1 on Dex VI

The are many suppliers of Dex VI and if you want AC Delco Dex VI it can be had for a reasonable cost at certain part stores. ( Canadian part number shown)

 

[Smith5361]

Ok then should i throw in the Lubeguard? Im tempted to do another pan drop since the last one was when i switched from III to VI and throw in the lubeguard at the same time.

 

[Smith5361]

Originally Posted by zeng
Consider ATF+4 .


Isnt that a Chrysler spec? What would be benefit of that?

 

[PiperOne]

Dex VI is fine...have a 4L85 here with over 450,000 on it. However...all Dex VI is not created equal....in fact the AC Delco stuff when we used it returned terrible samples. Switched to Chevron/Havoline Full Syn DexVI and problems went away immediately. Dex VI add packs are very similar to meet the licence spec...but the base oil varies. If you can keep the fluid under 170F it will handle anything you throw at it with ease.

 

[bullwinkle]

I've had Dex III/Mercon (mostly AAP brand) in the '93 GMC since I've had it, along with deep sump aluminum transmission pan & auxiliary cooler, highest temp I ever hit on the trans temp gauge was 210F, stuck in a traffic jam in summer while towing. Never an issue, most transmission guys I've dealt with have recommended sticking with Dex III-if it's not broke, why fix it? Maybe if I had a 454 dually and pulled a LOT more weight?

 

[Kira]

Re the LubeGard (red bottle).
A car I owned had a characteristic roughness in its shifting so the PO had it flushed at a dealership.
At 70K, when I bought it, it had crystal clear red fluid and the characteristic roughness.
I had the TCM reloaded and operation improved noticeably.
I added the prescribed dose of "red" (1 oz. per system quart) and well over half of the remaining roughness disappeared.

The bottle says it has a proprietary lubricant and makes transmissions run cooler.
I have no idea--I do not believe in snake oils--I won't be without the stuff.

My drain & fills = 3.5 qts. so 3.5 oz. of LubeGard goes in with 108.5 oz. of fluid.

I don't think it could possibly hurt and you sound like the kind of owner who'd notice any change.
Hopefully that change would be an improvement.

 

[mattwithcats]

TES 295 fluid...

Used in trucks, it's better than Dex III or Dex VI...

https://www.allisontransmission.com/parts-service/approved-fluids/on-highway-fluids

https://www.mobil.com/English-US/Commercial-Vehicle-Lube/pds/GLXXMobil-Delvac-1-ATF

Running it in my Saturn SL2 with manual transmission...

 

[dogememe]

I've had at least one older, high-mileage GM transmission start to have issues just days after switching from Dex III to Dex VI. As such, I'd suggest avoiding "low viscosity fuel efficient" ATF in older GMs that didn't originally spec Dex VI, despite the fact that Dex VI is a higher quality fluid and superior in pretty much every way.

 

[PiperOne]

Originally Posted by mattwithcats
TES 295 fluid...

Used in trucks, it's better than Dex III or Dex VI...

https://www.allisontransmission.com/parts-service/approved-fluids/on-highway-fluids

https://www.mobil.com/English-US/Commercial-Vehicle-Lube/pds/GLXXMobil-Delvac-1-ATF

Running it in my Saturn SL2 with manual transmission...



TES296 in a GM automatic is NOT a good idea. The transmission vintage of the OP has (or may have if it's a rebuild) many seals in it that are not TES295 friendly. 295 fluids are not just "better Dexron". 295 fluids are designed for Allison automatics...an all clutch architecture...not an older LD transmission that uses clutches, sprags and bands.

 

[Win]

I have a 4L80E in my Xj12, and just use plain Dexron - whatever is cheap, usually SuperTech or something from the local farm store. My pan has a drain plug, so I do a pan drain at every oil change.

I popped a line going to the cooler at triple digits one night, so that made for a complete fluid exchange on that fill ...

Mine is in a luxury car, so the TCM is programmed for fairly soft shifts; it is programmed to only use 2, 3, and 4, unless sport mode is selected.

 

[dave1251]

Originally Posted by PiperOne
Dex VI is fine...have a 4L85 here with over 450,000 on it. However...all Dex VI is not created equal....in fact the AC Delco stuff when we used it returned terrible samples. Switched to Chevron/Havoline Full Syn DexVI and problems went away immediately. Dex VI add packs are very similar to meet the licence spec...but the base oil varies. If you can keep the fluid under 170F it will handle anything you throw at it with ease.



The same rigorous spec is met.


https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3007594/1

 

[nthach]

Originally Posted by PiperOne
Originally Posted by mattwithcats
TES 295 fluid...

Used in trucks, it's better than Dex III or Dex VI...

https://www.allisontransmission.com/parts-service/approved-fluids/on-highway-fluids

https://www.mobil.com/English-US/Commercial-Vehicle-Lube/pds/GLXXMobil-Delvac-1-ATF

Running it in my Saturn SL2 with manual transmission...



TES296 in a GM automatic is NOT a good idea. The transmission vintage of the OP has (or may have if it's a rebuild) many seals in it that are not TES295 friendly. 295 fluids are not just "better Dexron". 295 fluids are designed for Allison automatics...an all clutch architecture...not an older LD transmission that uses clutches, sprags and bands.

I'm no ATF expert, but I would think if Allison back-speced TES295/TranSynd for their older trannies as well as the Allison 1000 and if the Chevron/Valvoline HD "synthetic" ATFs they recommend for Allison(but not certified) are also DexIII/Mercon compatible, it should be fine especially if the tranny was rebuilt with new seals. I wouldn't be surprised if TranSynd or any Allison TES295-approved fluid is using group III basestocks and not group V PAO/POE base.

Now, if I was the OP and money ain't a thing, I'd run Red Line or Amsoil Signature Series ATF. But I think any high-viscosity synthetic ATF will work nicely in an 4L80E.

 

[zeng]

Originally Posted by Smith5361
Originally Posted by zeng
Consider ATF+4 .


Isnt that a Chrysler spec? What would be benefit of that?

Chrysler spec, right.
ATF+4 has a high'ish 7.5 cSt as another Dexron 3, if not more .
It's as shear-stable as Dexron 6, though it's base oil is Group III.
Thus, it sort of combines Dexron 3 thicker viscosity and Dexron 6 shear-stability and likely to perform better and longer in components protection in applications calling for Dexron 3.

 

[DoubleWasp]

What of the friction characteristics? Would not a GM trans be unhappy with the grippier fluid?

 

[clinebarger]

Originally Posted by PiperOne
Originally Posted by mattwithcats
TES 295 fluid...

Used in trucks, it's better than Dex III or Dex VI...

https://www.allisontransmission.com/parts-service/approved-fluids/on-highway-fluids

https://www.mobil.com/English-US/Commercial-Vehicle-Lube/pds/GLXXMobil-Delvac-1-ATF

Running it in my Saturn SL2 with manual transmission...



TES296 in a GM automatic is NOT a good idea. The transmission vintage of the OP has (or may have if it's a rebuild) many seals in it that are not TES295 friendly. 295 fluids are not just "better Dexron". 295 fluids are designed for Allison automatics...an all clutch architecture...not an older LD transmission that uses clutches, sprags and bands.



TES-295 works very well in 4L80E's, The idea that it's only suitable for Clutch-to-Clutch Allison Automatics is absurd. Not to mention the original TES-295 Castrol Transynd had a Dexron IIIG approval/licence.

 

[Lubener]

Originally Posted by zeng
Originally Posted by Smith5361
Originally Posted by zeng
Consider ATF+4 .


Isnt that a Chrysler spec? What would be benefit of that?

Chrysler spec, right.
ATF+4 has a high'ish 7.5 cSt as another Dexron 3, if not more .
It's as shear-stable as Dexron 6, though it's base oil is Group III.
Thus, it sort of combines Dexron 3 thicker viscosity and Dexron 6 shear-stability and likely to perform better and longer in components protection in applications calling for Dexron 3.

Originally Posted by zeng

Consider ATF+4 .



Wouldn't think if ATF4 was better suited, GM would have stated that in a TSB? Just love these opinion based recommendations without the real facts to back them up.