4L60E Fluid

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Mar 18, 2021
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I have a 2003 S10 4.3 Automatic 2WD with a 4L60E transmission.

It currently has 123,000 miles on it I bought it last summer, runs good, shifts good, no slipping. I do not know the service history of this truck but I want it to last as long as possible and I believe there is a chance the transmission fluid is original.

The fluid in it is still a light pink/red with some slight dark spots when wiping it on paper towel. It does not smell burned and it seems to be in similar condition to my Toyota which was flushed 60,000 miles ago with Toyota T-IV which from my understanding is Dexron III with friction modifiers.

What I am stuck at is I do not know if it has the original Dexron III in it from the factory or if at some point it was serviced and if it was I don't know if they used a Dexron III compatible like Valvoline Dex/Merc or if they put Dexron VI in it.

GM is recommending I use Dexron VI but I don't want to harm it if it has Dexron III in it, I do not want to flush the transmission I simply want to drop the pan change the filter and fill it back up with fresh fluid.

Walmart has a good deal on Valvoline Dex/Merc $17 for 5 quarts.

Should I go with Dexron VI or should I go with Valvoline Dex/Merc and if the previous owner serviced it with one or the other is it safe if these 2 fluids mix because obviously a drain/fill is only going to get about 5 quarts out of the transmission.
 
Welcome to BITOG :)

You do not have to flush the transmission to switch to Dexron VI, and it is backwards-compatible to all GM automatic transmissions calling for earlier versions of Dexron.

Maxlife is very good ATF at a great price. $17 a gallon for good quality synthetic ATF is a great value.

I would also suggest you buy an aftermarket transmission pan that has a drain plug. It will make future ATF changes much easier.
 
I’m going to play devil’s advocate-if it’s worked fine so far, keep using standard Dex/Mercon. Unless you have overheating issues, or want to tow heavy (unlikely with an S-10), I’m not sure Dex VI is necessary. Clinebarger would be a good person to ask on here, he is the resident transmission expert here.
 
From what i have seen and have been able to gather the 4l60e is not super fluid picky. Pretty much anything that says dex iii or dex vi is going to do the job great. You can get a bunch of mag1 dex vi on rock auto for a good deal there is also usually ac delco dex vi on amazon for 20 a gallon. If neither of those suit your fancy you can run maxlife for the 17 bucks at Walmart or even the supertech dex/merc, high mileage or dexron vi. All of the dexron vi specific products in this list are licensed. My vote would be for maxlife due to cost, availability and going to hold up better than dex iii due to being a synthetic. You can find tons of anecdotes (including mine) that maxlife works great in gm transmissions.
 
You're ahead of the curve by servicing it at all.

I'd do a spill and fill with maxlife and call it a day. Repeat at the next oil change, and then again a couple more times after that. No need to flush.

That said, I have a bunch of dex/merc on the shelf and have been using it in my '99 Silverado that I bought used a few years ago.

Either way, you'll be fine. Do what makes you happy. FWIW, the large Valvoline ATF jugs are 4 quarts, not 5. Just remember that when you're planning and then refilling. :)
 
I’m going to play devil’s advocate-if it’s worked fine so far, keep using standard Dex/Mercon. Unless you have overheating issues, or want to tow heavy (unlikely with an S-10), I’m not sure Dex VI is necessary. Clinebarger would be a good person to ask on here, he is the resident transmission expert here.
Most it will tow is probably at some point is around 1500-2000lbs on occasions but that is not anytime soon, which is far below its 5,000lb towing capacity to begin with. But I do live in a very hilly state. I don't know what fluid is in this truck I don't know the service history so It may or may not have Dex/Merc in it.
 
Use licensed Dexron VI. It will say that specifically on the bottle. I am about to install a rebuilt 4L60E and got Valvoline's variety off of Amazon.

Valvoline's Maxlife is a good option, but it is not specifically a licensed Dexron VI. It is "recommended for" but not actual. It may be just as good or even better, but it doesn't have the license and Valvoline, of all companies, can certainly afford to get it for that fluid if they wanted to.

Even Walmart's SuperTech Dexron VI is fine. Relax about it.
 
I have a 4L60E in my 98 S-10 ZR2. It came with Dexron IIIH, which was rated for 105k of normal use. Of course I’ve changed mine sooner.

When Dex VI came out, I changed to that. The theory is that Dex III shears quite a bit, Dex VI doesn’t, and the Dex VI is about the same viscosity as a sheared Dex IIi.

Id drop the pan and run either with Lubeguard Red. Dex VI will be a great choice, but the standard D/M fluids will work fine too. It’s really your choice. Mixing them won’t do any harm, though Dex VI may clean marginally better.
 
You could do a cooler line flush followed by a pan drop and filter change. Definitely a 2 person job.

Connect a hose to the transmission to cooler line (not sure if top or bottom) and run the hose into a 5 gal bucket. Keep the transmission topped off by filling it through the dipstick tube.

To make the pan drop a little less messy, as soon as flow into the bucket starts to slow down and spewing air, turn the engine off. That should mostly drain the pan.
 
Consider the allison tes295 spec fluid, it is supposed to be a much more robust version of dex 3.
I don’t understand the push for this stuff. It’s about 2x the price of Maxlife ATF.

Thickness wise, it’s pretty close to Maxlife too. *5.9 (Maxlife) vs 7.3 cSt @ 100*C although I’m not sure what an actual DexIII would be.
 
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I’d probably feel ok with dex Vl, it’s backwards compatible.

I believe it is sold in both synthetic, blends and conventional.

I’d buy it on Amazon or at Walmart and be done with it.

And chances are if that fluid still looks red/pink after 120,000 miles, it’s been changed once already anyway.
 
I think castrol dex/merc is 24 a gal. Supertech dex v1 about the same. I put maxlife $17 in my 2003 Avalanche 4l60e and I tow 4k lbs.
Thinking of going supertech next time
 
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As a long time S10 owner, I can say if you're in a corrosion area, the powertrain will outlast the body panels.
I'd recommend Valvoline Maxlife for the trans and WoolWax for the body.
 
As a long time S10 owner, I can say if you're in a corrosion area, the powertrain will outlast the body panels.
I'd recommend Valvoline Maxlife for the trans and WoolWax for the body.
My S10 is rust free other then some very light surface rust on the frame in spots, same with a Blazer I owned. I will be wire brushing off surface rust and using corroseal.

As someone who lived in upstate ny before the salt will get you up there within a few years of owning an new car if you don't keep it under control, but in my current state although they put down salt still vehicles here just seem to hold up better.
 
I don’t understand the push for this stuff. It’s about 2x the price of Maxlife ATF.

Thickness wise, it’s pretty close to Maxlife too. *5.9 (Maxlife) vs 7.3 cSt @ 100*C although I’m not sure what an actual DexIII would be.
New Dex III would've been around 7-7.5Cst, maxlife is hydrocracked crude, TES-295 tend to have a good slug of PAO, TES-295 would probably last as a life time fill on a 4L60e, it's really meant to be a high viscosity transmission fluid that's incredibly stable to survive extended service intervals in large vehicles like semi truck, busses, garbage trucks, etc...
 
Use licensed Dexron VI. It will say that specifically on the bottle. I am about to install a rebuilt 4L60E and got Valvoline's variety off of Amazon.

Valvoline's Maxlife is a good option, but it is not specifically a licensed Dexron VI. It is "recommended for" but not actual. It may be just as good or even better, but it doesn't have the license and Valvoline, of all companies, can certainly afford to get it for that fluid if they wanted to.

Even Walmart's SuperTech Dexron VI is fine. Relax about it.
Which this also leads me to question why is maxlife not licensed. And I just find it odd that this maxlife says it is compatible with fluids of which are not compatible with each other such as Toyota T-IV and Toyota WS.

O'reilly has their brand of Dexron VI but now something I am confused about is there seems to be 2 different Dexron VI, the original and a full synthetic so what is up with that.
 
Which this also leads me to question why is maxlife not licensed. And I just find it odd that this maxlife says it is compatible with fluids of which are not compatible with each other such as Toyota T-IV and Toyota WS.

O'reilly has their brand of Dexron VI but now something I am confused about is there seems to be 2 different Dexron VI, the original and a full synthetic so what is up with that.
the license is a standardized set of tests, if a manufacturer so chooses to use a higher quality base oil and additives to meet that standard they are able to do so. As for why maxlife is not licensed it is anyones guess as to why that is. It could be valvoline being cheap, it could just not meet the requirements, it could be they just dont see the need and can coast off brand reputation. In any case there are TONs of anecdotes of maxlife working great in dexron vi, iii, etc transmissions. When they say they are the most popular brand of transmission fluid i do not doubt them.
 
Maxlife could also just not meet the specs in the manner of it is a solid middleground for most atf specs. I forgot who exactly it was on this forum but i believe it was one of the mods that had a signature for awhile that said something along the lines of "The simple act of maintenance is much more important than what it is maintained with... just use the maxlife" That is paraphrasing from memory so it may be a bit off but it was something along those lines. At the end of the day i would say clean fluid is better than dirty is the most important part.
 
From what I can tell plain licensed Dexron VI is kind of meh, the stuff that meets both Mercon LV and Dexron VI seems slighly superior to me seeing how the Dexron VI spec seems to allow for something like a brookfield viscosity of 13000cP at -40 while Mercon LV seems to be limited to around 10500cP, so the cold flow performance of Mercon LV seems more optimal than Dexron VI, Maxlife is only like 9000cP so that's pretty nice, but that's just one aspect of the fluid obviously,
 
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