ATS questions & concerns!

[Strick-9]

There was a post a few months ago entitled "questions and concerns about ATS's tripleloc. " The thread got bogged down with bystanders putting in their 2 cents like most automatic transmission threads do. I finally let that thread die because no one would answer my questions or show the actual pictures or flow diagrams. Now we have actual pictures and I still would like my questions answered.



No one will argue that a clutch pack is stronger than a single clutch of equal size and pressure applied. So why doesn't every single TC out there have a multiple disc lockup clutch. Ford, Chrysler, Chevrolet, Honda, Acura, etc. have millions and millions of dollars in R&D and have millions of ACTUAL engineering man-hours at their disposal. If even one of these companies had perfected the design it would be widespread throughout the industry as the standard. So obviously, there must be some MAJOR flaw in the design for a company like Chrysler to release a Dodge Cummins off the showroom floor without a multiple disc lockup clutch. The design has been around for decades. It's not an innovation by any means.



Let's look at this picture.

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When the converter is NOT in lockup (idle, park, reverse, stop-n-go traffic) flow of fluid enters through the input shaft into the very front of the converter (in front of the lockup piston). It exits between the pump reaction shaft and the input shaft (behind the lockup piston. ) We can now see for ourselves where the fluid is traveling. Look at the thin dark band around the outer edge of the front cover right where all the little teeth are. All of the fluid that enters the converter must be squeezed through this little region. This restriction causes a pressure drop across the clutches. The pressure drop forces the clutches into the piston and wears them out prematurely.



Now with this being the number one failure mode of multiple disc clutches in torque converters for decades, my question is what is done to help minimize this?



Keeping the torque converter locked all the times would minimize this problem and I see you are recommending locking the TC at 30 mph. Maybe that's why?



To sum it up. Was this problem addressed during the design? If so, what steps were taken to minimize this?



-Chris

 

[ATSDiesel]

First of all the fact is, these converters do not burn the friction rings and cooler flow is not restricted in the non-lock-up mode. Cooler flow is one of the best tools we have to determine real time oil passage between the clutch pack on the multiple clutch converters. Many of the questions that have been asked here are very good ones, the same questions we ask our self when we set out to bring this converter to the public. We used some crude methods to try to make certain elements of this converter fail. Some of them were setting clutch clearances to tight and running several hounded miles in fluid coupling to find potential failures that are difficult or impossible to calculate. This kind of abuse testing really helps point out long term failures that may not show up in modeling. We went through rigorous testing in ever area of this converter we could thank of from splines, endplay, thrust washers - bearings, clearances, friction compound, friction width, piston construction, etc.



The oil that passes around the center clutch passes evenly around the clutch steel because there is equal pressure on both sides of the steel/friction plate. This is the reason the clutch plates do not burn, and there are some other reasons why this works. The design of this converter is very complex when you get down to the actual working design of it. There are many small design features of this converter. Understand the development was shared between the Ford and the Cummins; we worked on the fluid circulation, lock-up control not to mention the stator design for a very long time to finally produce a converter that covers all areas. I can tell you that the Triple Loc converters we sell to our customers is a proven design.



Clint Cannon

www.ATSDieselPerformance.Com

 

[Strick-9]

First off. Thank you Clint for taking the time to try to answer.

The oil that passes around the center clutch passes evenly around the clutch steel because there is equal pressure on both sides of the steel/friction plate.

If that were true, why does the clutch plate move away from the front cover? With equal pressure on both sides, an object won't move. With equal pressures, the clutch would alway rub against the front cover. The piston obviously doesn't have equal pressures on it because it moves forward and backward. We all agree to that. We all want to believe that the clutch plates move away from the front cover and then stop moving sometime before they hit the piston. But, the same laws of physics that moved the clutch plate off the front cover still apply, and there is still a rearward force on the plate. The fact is, the plate will continue to move until it hits something. And that would be the piston or the next clutch plate.



Measuring cooler flow and checking for a loss of flow has nothing to do with this problem. The pump creates a specific volume of fluid. With each revolution of the pump a volume of fluid is pumped. The fluid goes directly to the pressure regulator valve. Whatever isn't needed to maintain line pressure goes through the converter and becomes cooler flow.



Volume of cooler flow won't change with a minor restriction. The only way the volume of cooler flow would diminish would be if the restriction was so great that cooler flow pressure became greater than line pressure. Then pressure would backup and increase line pressure until an equilibrium was reached again.



But you can still have a pressure drop in the cooler circuit without losing any volume flow.



I doubt this would show up in the few hundred miles of testing in fluid coupling. And I do believe you guys truly believe in your products.



Good luck,

Chris