CSTCC

Status
Not open for further replies.

MolaKule

Staff member
Joined
Jun 5, 2002
Messages
23,975
Location
Iowegia - USA
In order to provide smooth operation and economy in new transmission designs, Continuously Slipping Torque Converter Clutches have been incorporated.

1. Briefly describe the operation of these transmissions, and

2. What Type of Additive (Common, general name) must be incorporated in order to reduce low-speed shudder?
 
Man I'm such a sucker for trying this one....I know in laymans terms trannys need a more "friction modified" fluid to prevent shutter. I'm not sure if it is to help lock up or prevent lock up of the TC. (Mercon V would be an example of more FM than say Mercon). I've also heard of people using 1 qt of motor oil to gain enough FM to stop shutter....
 
The TC slips until it locks (3rd and 4th gear) to make the tranmission seem smoother.

Friction Modifer is needed to reduce shudder.
 
You got it DarkDan,

Vibrations (shudder or stick slip) in automatic transmissions (AT) caused by continuous slip torque converter clutches and shifting clutches are greatly reduced or eliminated by the use of special Friction-Modified fluids.

Automatic transmission fluids (ATF) are well known throughout the history of the automobile. In general however, automatic transmission suppliers and manufacturers specify performance characteristics of the transmission operating with a fluid rather than fluid composition for use in the transmission. It is then up to fluid providers to formulate fluids which meet performance characteristics. Recently, performance requirements for ATFs Service Fills have become more stringent with publication of DEXTRON-III ATF Specification by General Motors, GM 6297M, April, 1993. The Specification is available from General Motors, Material Engineering Transmissions, M/C 748 Ypsilanti, Mich 48197.

Low frequency vibration in continuous slip torque converter clutches (CSTCC) has been defined as shudder. The shudder vibration is related to stick slip friction characteristics of the engaged CSTCC rotating at slow speeds. Further, shudder has two components, initial shudder and shudder durability. The latter is shudder which develops over time.

Shuder is most prevalent during Breaking-in when the clutch surfaces are trying to flatten out.

Newly developed complex amines and other special additive chmicals make up the totality of the Friction-Modifiers in ATF fluid.

[ April 12, 2004, 02:36 PM: Message edited by: MolaKule ]
 
Status
Not open for further replies.
Back
Top