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If so what were the results?
Who has used a high viscosity transmission fluid in a LV application?
- Thread starter RazorsEdge
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2010 Camry is shifting fine on dex/merc at 220k. 2011 silverado has mostly dex/merc in it since it sprung a leak and has to be added constantly and is also shifting well at 100k. I personally don't think it makes as much difference as some make it out to be but its just anecdotal. If you don't want to take any "risk" then don't.
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In my opinion, I don't think it's that big of a deal. I'm curious more so if anyone has had any issues because I've seen it done.
MolaKule
Staff member
I have seen people use it but what they don't understand is 1) an ~ 1.25 cSt viscosity delta means very little in terms of system pressures and, 2) the LV fluids contain a more stable chemistry than the older 7.5 cSt fluids.
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I know @meep tried some Amsoil in his 10R80 and didn't like it at all. The 10R80 seems pretty sensitive to viscosity, which is probably why Ford has put big warmers/coolers on them. Both to bring them up to temp quick and to keep them cool.
I've messed with different fluids in my Honda vehicles with good results, but these 10 speeds are another beast.
I've messed with different fluids in my Honda vehicles with good results, but these 10 speeds are another beast.
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maximum efficiency requires maximum control
Yes. I use amsoil in all our vehicles and stand by it. However, while they recommended it for the 10r80…. I can’t believe they did. It clearly altered the characteristics of the transmission with about a 50% swap, slowing the shift precision and altering its feel during partial lockup (I think that’s what I was feeling). I dumped it and replaced with valvoline ULV. This was all to chase a problem which resolved beautifully after later adding just 2oz of LG red. Sure it was driveable, but it wasn’t right, lost its precision. Now with ULV and the LG, it’s almost as precise and out-of-the-way as the Lexus. The engineers really did their homework on the prgramming of that trans - it’s really that good when it’s happy. I’m not sure what happened between fluid chemistry and presumably the valve body materials. Cost cutting? Didn’t test the materials? Changed an o-ring material somewhere without testing?
I have toyota T4 in my 13 in sig which calls for WS. About 60k on T4....due for a change and going to try maxlife .220k on vehicle. I like the T4, I found it shifted a little smoother.
Those AISIN transmissions were originally designed for T4. WS is "working", but IMO that's just because the original pumps had enough head capacity to drop from.
The pump pressure regulator takes care of maintaining the right pressure if it tends to be too high, by dumping more fluid back in the pan. It just cannot "add" pressure if is too low.
On other hand, thicker fluid might just warm up more, due to increased losses, ending up with the same operational viscosity.
The best thing to do is cool that fluid. Even if is "LV", cooled just 10F might bring it's viscosity in line with what the non-LV has at 10F higher.
The pump pressure regulator takes care of maintaining the right pressure if it tends to be too high, by dumping more fluid back in the pan. It just cannot "add" pressure if is too low.
On other hand, thicker fluid might just warm up more, due to increased losses, ending up with the same operational viscosity.
The best thing to do is cool that fluid. Even if is "LV", cooled just 10F might bring it's viscosity in line with what the non-LV has at 10F higher.
You mean, people throwing around numbers (that they're repeating from others) that they actually don't know much, if anything, about ?
MolaKule
Staff member
The hydraulic system in an AT was designed to accommodate a wide variation in fluid viscosity from 2.5 cST@100C to more than 60 cSt@40C, which means using an oil pump design that is capable of sufficient flow and pressure over that range. It has nothing to do with "head drop."
The modern LV and ULV fluids are more viscosity stable than the older 7.5cSt fluids of yore, which means that if a LV fluid starts out at 5.8 cSt@100C, it will not shear down to a viscosity lower than than ~ 5.5 cSt at the same temp.
The older fluids might start out at 7.5cSt but shear down to 4.0cSt within 30k miles.
I would have thought that with all of the past threads on this topic and the topic of viscosity stability in the modern AT fluids, this would have been understood.
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You must be a chemist.
MolaKule
Staff member
One of many Analysis; you have to browse through BITOG's humongous data base of VOA's and UOA's: https://bobistheoilguy.com/forums/t...7-4cyl-ac60e-trans-79k-miles-on-fluid.342908/
Check the "Attributes:" https://attachments.priuschat.com/attachment-files/2020/02/182598_ATF_Type_WS_Data_Sheet_031218.pdf
Mobil WS Properties: https://www.mobil.com/en-th/passenger-vehicle-lube/pds/ap-xx-mobil-atf-ws
This guy's fluid sheared down 0.158 cSt over 79k.
As far as I have read to-date, you are the only one making this claim, and you never defined 'normal viscosity', but what has this to do with AT hydraulic pressures and ATF fluid properties?
One technique of proper discussion is to stay on topic.
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MolaKule
Staff member
Not so. Chemists have to study fluid mechanics and fluid systems, mechanical systems, and advanced chemistry to get a full picture of how a specific fluid should function in a specific mechanical environment.
Off topic again.
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What about modern full syn atfs, castrol transmax universal atf/cvt @ 7.1 cst or amsoil’s non lv synthetic fluid @ 7.5 cst, will these sheer at 30k or maintain their viscosity?
First off I was talking about Castrol, not the sh**show that Toyota WS is. That fluid is LV, but is not synthetic. Lots of modifiers. Oxidizes in no time.
And that 5.18 cSt result you call "they shear out at 30k miles and the end up lower than synthetic LV"? I don't know what the Toyota WS starts at, do you? No, because Toyota doesn't give that info, only the 40C value.
My question was: would shearing of a modern normal viscosity ATF make a drop from 7.1 to 5.0? You didn't prove that yet.
Because that's the theory that you and others vehiculate here.
I change my non-LV ATFs (usually Castrol) at 30-40k miles indeed, but it comes out almost identical. Only the Toyota WS and the Kia SP-IV factory fill got black/purple color in 50k miles.
Even the ones that make paints? Or food additives? Or cosmetics? Or a gazillion of other unrelated fields?
No chemistry college class will study the fluid flow or mechanical strength of materials better than a class in the mechanical engineering field.
And even those engineers come out of college unprepared for the real life... but yes, that's OT indeed.
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Mobil 3324 is Toyota WS
PdsDetailsPage
Mobil ATF™ 3324 is an exceptionally high performance lubricant that meets original equipment manufacturers' specifications for use in certain slip-controlled lock-up automatic transmissions.
www.mobil.com
take the loss gracefully before you embarrass yourself
MolaKule
Staff member
Yes, I do. The WS 100C viscosity spec is 5.3 cSt, + 0.5 cSt, - 0.3 cSt, and may be composed of Group III, IV and V base oils and additives.
PdsDetailsPage
Mobil ™ ATF WS is an exceptionally high performance lubricant that meets original equipment manufacturers' specifications for use in certain slip-controlled lock-up automatic transmissions.
www.mobil.com
Almost identical to what? Visual appearance tells you nothing as only a comprehensive analysis will really tell you the condition of the fluid.
Undoubtedly, you have never taken the full chemistry curriculum and your insistence on throwing in Off-topics indicates these are more emotional, rather than knowledgeable responses.