Castrol Transmax AFT/CVT Universal Fluid.

Grumpy Bear · March 13

?

Explain please.

Grumpy Bear · March 14

Claim is it suitable for nearly any current transmission of any type. Pretty exhaustive list.

https://www.castrol.com/content/dam/castrol/country-sites-new/en_us/united-states/home/documents/product/transmax-universal-full-application-sheet-2_24.pdf

Cures acne too!

So, explain please how a single fluid can do these jobs. I'm clueless on this one.

customboss · March 14

12 hours ago, Grumpy Bear said:

Claim is it suitable for nearly any current transmission of any type. Pretty exhaustive list.

https://www.castrol.com/content/dam/castrol/country-sites-new/en_us/united-states/home/documents/product/transmax-universal-full-application-sheet-2_24.pdf

Cures acne too!

So, explain please how a single fluid can do these jobs. I'm clueless on this one.

Before I study this product, I agree.

How about my carpel tunnel and cubital tunnel issues ? Acne long gone about ~ 55 years ago?

customboss · March 14

Oh my BE CAREFUL ignorant consumer running into Oreillys and grabbing the product placement help them select.

JATCO CVT not able to use. I had to go through all the the applications and did so miss something?

Deep dive maybe? most fine print apps mean trans fluid recommended.

Means traction coefficient issues with JATCO chain linked type chain issues.

Why oh why!

Grumpy Bear · March 14

1 hour ago, customboss said:

Oh my BE CAREFUL ignorant consumer running into Oreillys and grabbing the product placement help them select.

JATCO CVT not able to use. I had to go through all the the applications and did so miss something?

Deep dive maybe? most fine print apps mean trans fluid recommended.

Means traction coefficient issues with JATCO chain linked type chain issues.

Why oh why!

The the manual for my JATCO FJ015E specifies J4 fluid. Go further down page #2. You will find it listed under the CVT applications. Mitsubishi CVTF ECO J4

customboss · March 14

4 hours ago, Grumpy Bear said:

The the manual for my JATCO FJ015E specifies J4 fluid. Go further down page #2. You will find it listed under the CVT applications. Mitsubishi CVTF ECO J4

I wouldn’t try it.

Grumpy Bear · March 15

2 hours ago, customboss said:

I wouldn’t try it.

I had no plan to. Was hoping for a bit of input on the idea of universal fluids. Thoughts? Specific is good. Only if your up for it.

customboss · March 15

6 minutes ago, Grumpy Bear said:

I had no plan to. Was hoping for a bit of input on the idea of universal fluids. Thoughts? Specific is good. Only if your up for it.

It’s can be done if you do alot of confirmation testing. But you’re going to have to block out many applications or screw the consumer.
Valvoline did a great job with the their Maxlife full GRP III product for auto trans

Grumpy Bear · March 15

Well all-righty then That rabbit hole wasn't to deep. Thank you for having a look.

customboss · March 15

13 minutes ago, Grumpy Bear said:

Well all-righty then That rabbit hole wasn't to deep. Thank you for having a look.

I’ll give a deeper dive but by this time In Evening my brain melts.

customboss · March 16

On 3/14/2025 at 11:59 AM, Grumpy Bear said:

The the manual for my JATCO FJ015E specifies J4 fluid. Go further down page #2. You will find it listed under the CVT applications. Mitsubishi CVTF ECO J4

“. *”Suitable for use” means that, based on testing (and technical judgments) by Castrol (and its suppliers), a fluid meets the

performance requirements and other attributes of a particular specification, making it suitable for use in that specification. This

is compared to an “OEM Approved" fluid which has gone through the OEM approval process and has been formally approved by

the OEM for use in a particular specification.

When performing a transmission fluid change with any Transmax multi-vehicle ATF, Castrol guidance to IWS/quick

lubes/transmission specialists is that all measures must be taken to ensure that any existing fluid in the vehicle is removed first.

Castrol cannot guarantee performance of mixed fluids. When draining fluid from a transmission, ensure that the entire system is

drained as much as physically possible before re-filling with Castrol fluid. Always refer to OEM manuals and maintenance

bulletins to ensure that any equipment-specific considerations are kept in mind.”

customboss · March 16

1 minute ago, customboss said:

“. *”Suitable for use” means that, based on testing (and technical judgments) by Castrol (and its suppliers), a fluid meets the

performance requirements and other attributes of a particular specification, making it suitable for use in that specification. This

is compared to an “OEM Approved" fluid which has gone through the OEM approval process and has been formally approved by

the OEM for use in a particular specification.

When performing a transmission fluid change with any Transmax multi-vehicle ATF, Castrol guidance to IWS/quick

lubes/transmission specialists is that all measures must be taken to ensure that any existing fluid in the vehicle is removed first.

Castrol cannot guarantee performance of mixed fluids. When draining fluid from a transmission, ensure that the entire system is

drained as much as physically possible before re-filling with Castrol fluid. Always refer to OEM manuals and maintenance

bulletins to ensure that any equipment-specific considerations are kept in mind.”

A lot of “outs” there for the marketing company known as CASTROL. Their R&D used to be wonderful but their blending quality at world wide toll blenders sucked.
Aramco is looking to buy Castrol too.

Edited March 16 by customboss

customboss · March 16

Ok Grumpy here ya go for as deep as I can go.

CVT dynamics: Theory and experiments

ATF vs CVT

CVT Dynamics and Transmission Fluid Study Guide

Quiz

Instructions: Answer the following questions in 2-3 sentences each, based on the provided source materials.

What is the primary motivation for the increased interest in Continuously Variable Transmissions (CVTs) in vehicles?
According to the CMM model, what is the crucial role of pulley bending during slow shifting in a V-belt CVT?
State the relationship that the CMM model predicts between the rate of change of the speed ratio and the clamping force ratio during creep-mode shifting.
What key finding resulted from the dimensional analysis of the CVT system under no-load conditions, and what does this suggest about the relationship between shifting speed and clamping forces?
How did the CMM model's predictions for a chain belt CVT compare with the results obtained using Tenberge's FEM approach? What was a significant conclusion from this comparison?
According to the experimental validation, what parameters did not significantly influence the equilibrium clamping force ratio (SDR/SDN)eq in steady-state no-load tests?
What key observation from the shifting measurements experimentally confirmed a significant prediction of the CMM model regarding the relationship between shifting speed and clamping forces?
According to the source on transmission fluids, what is a fundamental difference in the mechanical operation of a CVT compared to a traditional automatic transmission?
What are two key properties that differentiate CVT fluid from Automatic Transmission Fluid (ATF) due to the specific requirements of CVT systems?
What are the potential consequences of mixing CVT fluid and ATF in a vehicle's transmission system, and why is this detrimental?

Quiz Answer Key

The primary motivation for the increased interest in CVTs is growing environmental concerns and the need to reduce vehicle emissions. CVTs offer an infinite number of gear ratios, allowing engines to operate closer to their optimal efficiency, potentially leading to fuel savings.
The CMM model emphasizes that pulley bending plays a crucial role during creep-mode (slow) shifting by influencing the varying groove angle and axial displacement of the pulley sheaves, directly affecting the belt's radial position and the shifting response.
During creep-mode shifting, the CMM model predicts a linear relationship between the rate of change of the speed ratio and the logarithm of the clamping force ratio (SDR/SDN). This logarithmic dependence is a key finding of the model.
Dimensional analysis under no-load conditions suggests a simplified relationship for the shifting speed based on the speed ratio and clamping force ratio, indicating that the linear relationship between the logarithm of the clamping force ratio and shifting speed is a robust property.
The CMM model's predictions for a chain belt CVT showed very good agreement with Tenberge's more complex FEM approach regarding sliding velocity, friction forces, and clamping forces, suggesting that the simpler CMM model can provide accurate results despite the discrete nature of chain belts.
Experimental no-load tests showed that neither the magnitude of the secondary clamping force (SDN) nor the angular velocity of the primary pulley (ωDR) had a significant influence on the equilibrium clamping force ratio (SDR/SDN)eq in steady-state.
The shifting measurements showed that for fixed values of speed ratio (s) and secondary clamping force (SDN), the plotted data of ln(SDR/SDN) as a function of shifting speed (ṡ) fell on a straight line, confirming the linear dependence of ṡ on ln(SDR/SDN) predicted by the CMM model.
A fundamental difference is that CVTs utilize two pulleys linked by a belt to achieve an infinite number of gear ratios, whereas traditional automatic transmissions rely on a system of regular gears to provide a discrete number of gear ratios.
Two key properties differentiating CVT fluid from ATF are its unique frictional properties to accommodate the belt-and-pulley system (higher friction in some aspects) and its high shear stability to withstand the forces within a CVT.
Mixing CVT fluid and ATF is detrimental because they are formulated for the precise specifications of their respective transmission systems. This intermixing can lead to reduced friction in CVTs causing slippage, or increased friction in automatic transmissions causing excessive drag, potentially leading to performance issues and damage.

Essay Format Questions

Critically analyze the CMM model's theoretical framework for understanding V-belt CVT dynamics. Discuss its key assumptions, the role of pulley deformation, and the significance of the predicted linear relationship between shifting speed and the logarithm of the clamping force ratio.
Evaluate the experimental validation of the CMM model presented in the source materials. Discuss the strengths and limitations of the experimental setup, the types of tests conducted (steady-state and shifting), and the extent to which the experimental results support the model's predictions for both V-belt and chain belt CVTs.
Discuss the implications of the CMM model and its experimental validation for the design and control of CVT systems. How can the findings, particularly the proposed differential equation for creep-mode evolution, be utilized to improve CVT efficiency, drivability, and fuel economy in vehicles?
Compare and contrast the functional requirements and properties of CVT fluid and Automatic Transmission Fluid (ATF) as described in the source materials. Explain why it is crucial to use the correct type of fluid for each transmission system and the potential consequences of using the wrong fluid or mixing them.
Synthesize the information from both source materials to provide a comprehensive overview of the challenges and advancements in CVT technology. Discuss the benefits of CVTs in terms of fuel efficiency and emissions, the theoretical models used to understand their dynamics, and the specialized fluids required for their optimal operation and longevity.

Glossary of Key Terms

Continuously Variable Transmission (CVT): A type of automatic transmission that can seamlessly change through an effectively infinite number of gear ratios within its operational range, providing smoother acceleration and potentially better fuel efficiency.
Speed Ratio (s): The ratio of the rotational speed of the driving pulley to the rotational speed of the driven pulley in a CVT. Mathematically represented as $s = R_{DR}/R_{DN}$, where $R_{DR}$ and $R_{DN}$ are the radii of the driving and driven pulleys, respectively.
Creep-Mode Shifting: Slow shifting of the speed ratio in a CVT, characterized by a specific relationship between the rate of change of the speed ratio and the clamping forces.
Clamping Force: The axial force applied to the movable pulleys in a CVT to ensure sufficient friction and power transmission with the belt. SDR refers to the clamping force on the driving pulley, and SDN refers to the clamping force on the driven pulley.
CMM Model: The Carbone, Mangialardi, Mantriota theoretical model that describes both the steady-state and shifting behavior of V-belt CVTs, emphasizing the role of pulley deformation.
Pulley Deformation: The bending and elastic axial displacement of the CVT pulleys under load, which significantly influences the groove angle and belt contact.
Sattler's Model: A model used within the CMM theory to describe the varying groove angle and axial displacement of the pulley sheaves based on trigonometric functions.
Dimensionless Parameter A: A parameter introduced in the paper (Eq. 16) that relates the rate of change of the pulley radius to the primary pulley's angular velocity and radius, used to analyze shifting dynamics.
Equilibrium Clamping Force Ratio ((SDR/SDN)eq): The ratio of the driving to driven pulley clamping forces when the CVT is operating in a steady-state condition (i.e., the speed ratio is not changing).
Automatic Transmission Fluid (ATF): A specialized lubricant designed for traditional automatic transmissions that use gears, formulated for friction reduction and hydraulic function.
CVT Fluid: A specialized lubricant designed for Continuously Variable Transmissions that use belts and pulleys, formulated with unique frictional and shear stability properties to meet the specific demands of CVT systems.
Shear Stability: The ability of a fluid to resist viscosity loss when subjected to high shear stresses, important in CVTs due to the belt-pulley contact forces.
Thermal Stability: The ability of a fluid to resist degradation and maintain its properties at high operating temperatures, common in transmission systems.

Edited March 16 by customboss

customboss · March 16

Why Castrol developed this.......95% coverage with a lot of exceptions in small print.

Grumpy Bear · March 16

10 minutes ago, customboss said:

Two key properties differentiating CVT fluid from ATF are its unique frictional properties to accommodate the belt-and-pulley system (higher friction in some aspects) and its high shear stability to withstand the forces within a CVT.

Mixing CVT fluid and ATF is detrimental because they are formulated for the precise specifications of their respective transmission systems. This intermixing can lead to reduced friction in CVTs causing slippage, or increased friction in automatic transmissions causing excessive drag, potentially leading to performance issues and damage.

(Above) That was what I was after.

55 minutes ago, customboss said:

When performing a transmission fluid change with any Transmax multi-vehicle ATF, Castrol guidance to IWS/quick lubes/transmission specialists is that all measures must be taken to ensure that any existing fluid in the vehicle is removed first.

Castrol cannot guarantee performance of mixed fluids. When draining fluid from a transmission, ensure that the entire system is drained as much as physically possible before re-filling with Castrol fluid. Always refer to OEM manuals and maintenance bulletins to ensure that any equipment-specific considerations are kept in mind.”

Marketing. Read the fine print. Thank you @customboss. Nice work.