Ls1 transmission fluid
So, I read Valvolines Maxlife ATF #1 is the best for high performance engines. Can we/should we use this in are highly modified LS1's or not?
Their website filter doesn't have 98-03, just LT1s.Whats up with that? Unless some panzie punk is hacking my computer.
Can someone check this, please? Their compatible sheet doesn't list DEX III or IV. I read that ATF can be used for VI, and IV replaced III. Mobil 1's site states their high performance TF is not compatible. Who the hell came up with Roman numbers why didn't they just use ENGLISH numbers? Why is Mobil 1 high performance engine oil the best for our engine but no transmission fluid. Doesn't make sense. What's the best high performance LS1 Transmission fluid?
Are Red Lines products good?
Their website filter doesn't have 98-03, just LT1s.Whats up with that? Unless some panzie punk is hacking my computer.
Can someone check this, please? Their compatible sheet doesn't list DEX III or IV. I read that ATF can be used for VI, and IV replaced III. Mobil 1's site states their high performance TF is not compatible. Who the hell came up with Roman numbers why didn't they just use ENGLISH numbers? Why is Mobil 1 high performance engine oil the best for our engine but no transmission fluid. Doesn't make sense. What's the best high performance LS1 Transmission fluid?Are Red Lines products good?
Last edited by JJT89; Apr 22, 2025 at 02:54 AM. Reason: add more info
Redline is top notch stuff and so is Valvaline I’ve used both in the past. Last flush I used AC Delco VI cause summit racing was having a sale on 5qt jugs.
Fresh transmission fluid is the most important part. It’s just hydraulic fluid after all.
Fresh transmission fluid is the most important part. It’s just hydraulic fluid after all.
So, I read Valvolines Maxlife ATF #1 is the best for high performance engines. Can we/should we use this in are highly modified LS1's or not?
Their website filter doesn't have 98-03, just LT1s.Whats up with that? Unless some panzie punk is hacking my computer.
Can someone check this, please? Their compatible sheet doesn't list DEX III or IV. I read that ATF can be used for VI, and IV replaced III. Mobil 1's site states their high performance TF is not compatible. Who the hell came up with Roman numbers why didn't they just use ENGLISH numbers? Why is Mobil 1 high performance engine oil the best for our engine but no transmission fluid. Doesn't make sense. What's the best high performance LS1 Transmission fluid?
Are Red Lines products good?
Their website filter doesn't have 98-03, just LT1s.Whats up with that? Unless some panzie punk is hacking my computer.
Can someone check this, please? Their compatible sheet doesn't list DEX III or IV. I read that ATF can be used for VI, and IV replaced III. Mobil 1's site states their high performance TF is not compatible. Who the hell came up with Roman numbers why didn't they just use ENGLISH numbers? Why is Mobil 1 high performance engine oil the best for our engine but no transmission fluid. Doesn't make sense. What's the best high performance LS1 Transmission fluid?Are Red Lines products good?
I have no preference to trans oils. For the 60e or 80e anything that meets of exceeds dex 3 requirement's is fine, I use DEX 6 in my own car 1995 impala SS I think it calls for dex 3 or dexmercron.
Synths have a better heat tolerance . But as menton it's just hydraulic oil. Dex and higher have friction modifiers to mostly avoid Converter clutch chatter with PWM converter clutch operation.
Most important is as also mentioned its clean.
I'm not much for snake oils for trans though I will suggest lube guard when someone runs into converter chatter from using non dex 3 or higher oils or really cheap oil that was supposed to meet that standard (some no name oils are a crap shoot for whats they actually are)
BUT IMO they is no extra special HIGH PERFORMANCE trans fluid .
Synths have a better heat tolerance . But as menton it's just hydraulic oil. Dex and higher have friction modifiers to mostly avoid Converter clutch chatter with PWM converter clutch operation.
Most important is as also mentioned its clean.
I'm not much for snake oils for trans though I will suggest lube guard when someone runs into converter chatter from using non dex 3 or higher oils or really cheap oil that was supposed to meet that standard (some no name oils are a crap shoot for whats they actually are)
BUT IMO they is no extra special HIGH PERFORMANCE trans fluid .
There is no such thing as English numbers. They are Arabic numerals, and their history goes back far enough for the origins to get a little murky. I'm not touching the rest of the bullshit in that post with a ten foot pole.
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From: Schiller Park, IL Member: #317

Beyond that, I've never moved away from Dex III (now just Dex/Merc), usually Valvoline brand. I use this in my TH350s as well as my 4L60E, works just fine.
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Bottom line is that the 4L60E was born to use Dexron III (3) as factory fill. In 2005 GM came out with the 6T70 and Dexron VI as factory fill. The 6L80 for Cadillac and it used Dexron VI (6) as factory fill. For 2007 the New body truck got the 6L80, yes they still used the 4L60E through 2014 in some applications but Dexron VI (6) was now factory fill as of 2006.
Dexron VI replaced Dexron 3 in 2006...
Dexron VI will give you a better cold drivability, better heat protection and has a longer service life over Dexron III.
There was no Dexron IV (4) ever... Most of the time people are confusing Mopar ATF +4 and Dexron VI or getting the Roman numerals switched around.
Here is the link to the wikipedia page on Dexron fluids and how it evolved.
https://en.wikipedia.org/wiki/DEXRON
Dexron VI replaced Dexron 3 in 2006...
Dexron VI will give you a better cold drivability, better heat protection and has a longer service life over Dexron III.
There was no Dexron IV (4) ever... Most of the time people are confusing Mopar ATF +4 and Dexron VI or getting the Roman numerals switched around.
Here is the link to the wikipedia page on Dexron fluids and how it evolved.
https://en.wikipedia.org/wiki/DEXRON
Thanks for the info everyone. I got confused cause later today I found out there was a 6 I didn't know that I thought 5 was the last one. Plus Valvoline's website not having 98-02 F bodies in their Vehicle Filter didn't help.
O..and I guess you don't have a 10 foot pole... Not you Trazman...
O..and I guess you don't have a 10 foot pole... Not you Trazman...
You are correct, that is a negligible difference between those two brands.
Yes Dexron 3 is inherently thicker because it is a mineral oil base stock. Valvoline shows it a 7.1 viscosity at 212 degrees and a 34.5 at 104 degrees. It got a lot thicker at "0" degrees.
That is why the Dexron VI gives you a better cold drivability.
Yes Dexron 3 is inherently thicker because it is a mineral oil base stock. Valvoline shows it a 7.1 viscosity at 212 degrees and a 34.5 at 104 degrees. It got a lot thicker at "0" degrees.
That is why the Dexron VI gives you a better cold drivability.
















