# Dextron VI tranny fluid in older 4L60E?



## 70monte (Feb 5, 2008)

I have a 1998 Chevy K1500 with the above tranny. Has anyone used the new Dextron VI tranny fluid in an older 4L60E or 4L80E and did you have any issues?

Some of the Dextron VI's I've seen are fully synthetic and some are a blend. Years ago I ran Mobil 1 fully synthetic in this truck and it didn't seem to like it. It always felt like it was slipping. That quit when I changed back to a conventional fluid.

I'm kind of hesitant to use Dextron VI since it does have some synthetic in it and I don't want to have the same issues I had with the Mobil 1, but there is no longer any approved Dextron III's on the market anymore so I'm not sure how good the Dextron III generic fluid is.

What are you guys using if you are not using a Dextron VI? Thanks.

Wayne


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## brad96z28 (Aug 21, 2005)

valvoline dex 6 is full synthetic. I like it in my allison.


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## B&B (Nov 4, 2006)

About the only thing D6 is good for are applications that specifically call for it (06-up), those still under an OEM powertain warranty, and creating heat in a waste oil furnace. Otherwise wouldn't run it even if they gave it away for free. Especially in a non originally spec'ed application.


Brad you know D6 has been proven to cause seal issues in the 5-speeds Ally's?


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## mpriester (Oct 2, 2011)

what is the best to run in a 05 2500hd?


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## theholycow (Nov 29, 2002)

Your googling will work better if you search for Dexron instead of Dextron.

GM is no longer licensing the Dexron III approval. Dexron VI supercedes it and GM officially insists that you should use Dexron VI in all applications that specify Dexron III.

There are probably a whole bunch of TSBs, but this is the first one I googled up:



Summary of TSB said:


> Bulletin No.:04-07-30-037C	Date: 4/11/2007
> 
> Subject: Release of DEXRON(R)-VI Automatic Transmission Fluid (ATF)
> 
> ...


Sounds good, and a friend who really knows the 4L60E inside and out is using DexVI...but my 4L60E has been great for 211,000 miles on DexIII, so DexIII I shall continue to use.


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## brad96z28 (Aug 21, 2005)

B&B;1524371 said:


> About the only thing D6 is good for are applications that specifically call for it (06-up), those still under an OEM powertain warranty, and creating heat in a waste oil furnace. Otherwise wouldn't run it even if they gave it away for free. Especially in a non originally spec'ed application.
> 
> Brad you know D6 has been proven to cause seal issues in the 5-speeds Ally's?


 Ive never read where anyone has personally had trouble more he said she said. Pages and pages of people on diesel page including my self that is hasve not had any trouble with the dex 6. Another thing I have read was the gm dex 6 is a synthetic blend and thats what causes problems. I dont believe everything I read. I do know the transynd is far superor.


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## 70monte (Feb 5, 2008)

LOL, I didn't even notice I was spelling it wrong. So, what do you recommend I run? Do you guys trust the non-licensed Dextron III out there?

I did use Valvoline Dextron VI in my 2004 Supercharged Monte Carlo when I first got it three years ago and it doesn't seem to have any issues but I have read on the Monte Carlo forum I go to that some people have had issues. Thanks for the input.

Wayne


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## B&B (Nov 4, 2006)

brad96z28;1525051 said:


> Ive never read where anyone has personally had trouble more he said she said. Pages and pages of people on diesel page including my self that is hasve not had any trouble with the dex 6. Another thing I have read was the gm dex 6 is a synthetic blend and thats what causes problems. I dont believe everything I read. I do know the transynd is far superor.


 We've had multiple units leak that were directly related to the owner swapping to Dex6. So this is first hand experience. Three were with full synthetic (Valvoline) and the remaining were Dex6 blends, and all were before the trans s/n break point. In all cases after a couple drain/re-fills back to either dino Dex3, Torque-Drive or Transynd they all "magically" fixed themselves and have had no further leaks to date.

I've found the older transmissions (4L60E/80E etc) still work better on Dex3 either dino or synthetic as well. Especially if they have some age they tend to get (more) mushy on the upshifts and will sometimes set a slip code (mostly on the 60E's) for the 3-4 shift. Go back to Dex3 and it all goes away.


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## theholycow (Nov 29, 2002)

Nobody's changing the formula on their Dexron III products just because GM isn't officially licensing the name "Dexron III" anymore. I use Walmart's "SuperTech" brand Dexron III and intend to continue using it. If they discontinue it I'll use whatever brand is still selling Dexron III. I know it works in my 4L60E and my T5, and my wife's 4L30E and her TH350...I stock one fluid and it works on everything, I'm not messing with it. I suspect Dexron VI would work fine, but why mess with success? 

In short: Dexron III ain't broke so I won't fix it.


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## 70monte (Feb 5, 2008)

I am running Supertech Dexron III in my 98 K3500 and Chevron Dexron III in the K1500. I only have three bottles of the Chevron left so I was looking for a replacement. I will just continue to use the Supertech stuff.

As a side note, I was reading a TSB that said you are not supposed to use Dexron VI in transfer cases that require Dexron III and to use GM fluid #88861800 which is labled as a manual transmission and transfer case fluid and is supposedly just Dexron III. If this is true, then GM is still requiring a Dexron III fluid in some of their components and that Dexron VI wasn't the complete replacement fluid they first thought it would be. It's pricy at over $6 a quart.

Wayne


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## DieselSlug (Nov 30, 2009)

I just got my trans rebuilt ~4k miles ago. When i installed i was debating on what to fill with. Ended up installing Dexron VI. NAPA actually recommended it. I also did some researching on the web. Its supposed to stand heat better, and reduce wear. So far no issues. 4L80E.


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## 70monte (Feb 5, 2008)

Thanks for the info. My 98 K3500 has the 4L80E. I used Supertech Dexron III five years ago after I got the truck. I didn't know if using Dexron VI would cause any issues. I have been reading various posts on the internet about using Dexron VI in pre-2006 vehicles that called for Dexron IIE and III and they have not been all good so I didn't know what to think. I just know I didn't like how my 4L60E shifted with fully synthetic Mobil 1 so I'm leery about using any type of synthetic in this trans, even if it's only a blend.

Wayne


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## DieselSlug (Nov 30, 2009)

Np. I used Napa dexron. And insider told me Napa fluids are rebadged valvoline products.


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## Newdude (Dec 4, 2006)

You could put either in there. If you would rather feel safer on your older trans, put Dex3 in there. Friend of mine put Dex6 in his 1995 when we did his shift kit a couple years ago and its running strong.



B&B;1524371 said:


> Brad you know D6 has been proven to cause seal issues in the 5-speeds Ally's?


Transynd all the way!!!


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## brad96z28 (Aug 21, 2005)

B&B;1525157 said:


> We've had multiple units leak that were directly related to the owner swapping to Dex6. So this is first hand experience. Three were with full synthetic (Valvoline) and the remaining were Dex6 blends, and all were before the trans s/n break point. In all cases after a couple drain/re-fills back to either dino Dex3, Torque-Drive or Transynd they all "magically" fixed themselves and have had no further leaks to date.
> 
> I've found the older transmissions (4L60E/80E etc) still work better on Dex3 either dino or synthetic as well. Especially if they have some age they tend to get (more) mushy on the upshifts and will sometimes set a slip code (mostly on the 60E's) for the 3-4 shift. Go back to Dex3 and it all goes away.


The dex 6 has been in a year and a half maybe 2 years now. I might swap it with something else in another 20k Got to have atleast that on it now..


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## 70monte (Feb 5, 2008)

When I changed my tranny fluid in my 92 cavalier last year, I used Supertech Dexron VI and all seemed well, but recently the trans doesn't seem to be shifting that well. The car does have 177,000 miles on it so that could have something to do with it but I have always changed the tranny fluid at between 15,000-20,000 miles on this car since I got it six years ago with 76,000 miles on it. I think the fluid spec for this trans is Dexron IIE. It is due for another change soon and I may go back to a Dexron III. Thanks again.

Wayne


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## 2COR517 (Oct 23, 2008)

B&B;1525157 said:


> We've had multiple units leak that were directly related to the owner swapping to Dex6. So this is first hand experience. Three were with full synthetic (Valvoline) and the remaining were Dex6 blends, and all were before the trans s/n break point. In all cases after a couple drain/re-fills back to either dino Dex3, Torque-Drive or Transynd they all "magically" fixed themselves and have had no further leaks to date.
> 
> I've found the older transmissions (4L60E/80E etc) still work better on Dex3 either dino or synthetic as well. Especially if they have some age they tend to get (more) mushy on the upshifts and will sometimes set a slip code (mostly on the 60E's) for the 3-4 shift. Go back to Dex3 and it all goes away.


Sounds like it's Dex 3 or Mobil 1 for the 02? No Dex 6 regardless of brand or formula.


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## B&B (Nov 4, 2006)

2COR517;1526437 said:


> Sounds like it's Dex 3 or Mobil 1 for the 02? No Dex 6 regardless of brand or formula.


Correct and if you decide on Dex3 dino throw in a dose of Lubgard too. Lena with thank you.


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