400 Commonwealth Drive, Warrendale, PA 15096-0001 U.S.A. Tel: (724) 776-4841 Fax: (724) 776-5760 SAE TECHNICAL PAPER SERIES 1999-01-3616 Anti-Shudder Mechanism of ATF Additives at Slip-Controlled Lock-Up Clutch Mamoru Tohyama and Toshihide Ohmori Toyota Central R&D Labs., Inc Fumio Ueda Toyota Motor Corp. International Fall Fuels & Lubricants Meeting & Exposition Toronto, Ontario, Canada October 25-28, 1999Downloaded from SAE International by University of New South Wales, Tuesday, September 18, 2018The appearance of this ISSN code at the bottom of this page indicates SAE’s consent that copies of the paper may be made for personal or internal use of specific clients. This consent is given on the condition,however, that the copier pay a $7.00 per article copy fee through the Copyright Clearance Center, Inc.Operations Center, 222 Rosewood Drive, Danvers, MA 01923 for copying beyond that permitted by Sec-tions 107 or 108 of the U.S. Copyright Law. This consent does not extend to other kinds of copying such ascopying for general distribution, for advertising or promotional purposes, for creating new collective works,or for resale. SAE routinely stocks printed papers for a period of three years following date of publication. Direct your orders to SAE Customer Sales and Satisfaction Department. Quantity reprint rates can be obtained from the Customer Sales and Satisfaction Department.To request permission to reprint a technical paper or permission to use copyrighted SAE publications in other works, contact the SAE Publications Group. No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior wr itten permission of the publisher. ISSN 0148-7191 Copyright 1999 Society of Automotive Engineers, Inc. Positions and opinions advanced in this paper are those of the author(s) and not necessarily those of SAE. The author is solely responsible for the content of the paper. A process is available by which discussions will be printed with the paper if it is p ublished in SAE Transactions. For permission to publish this paper in full or in part, contact the SAE Publications Group. Persons wishing to submit papers to be considered for presentation or publication through SAE should send the manuscript or a 3 00 word abstract of a proposed manuscript to: Secretary, Engineering Meetings Board, SAE. Printed in USAAll SAE papers, standards, and selected books are abstracted and indexed in the Global Mobility DatabaseDownloaded from SAE International by University of New South Wales, Tuesday, September 18, 20181 1999-01-3616 Anti-Shudder Mechanism of ATF Additives at Slip-Controlled Lock-Up Clutch Mamoru Tohyama and Toshihide Ohmori Toyota Central R&D Labs., Inc Fumio Ueda Toyota Motor Corp. Copyright © 1999 Society of Automotive Engineers, Inc. ABSTRACT The anti-shudder effect of ATF additives and their mecha- nisms have been investigated. Anti-shudder durabilitywas evaluated using an automatic transmission (AT) onan engine stand under continuously slip-controlled condi-tion. The addition of over-based Ca-sulfonate and frictionmodifier (FM) remarkably improved the anti-shudderdurability of ATF. The surface roughness of the contact area (contact area roughness) of the clutch plates was measured by anelectron probe surface roughness analyzer. To evaluatethe boundary frictional properties of the adsorbed filmformed, the friction coefficient of the clutch plates in theabsence of oil was examined after the anti-shudder dura-bility test. It was found that shudder occurrence was strongly corre- lated with the contact area roughness and the boundaryfrictional property of the steel plate surface. Large con-tact area roughness and low boundary friction were pre-ferred to prevent shudder. It was suggested that theincrease in the contact area roughness was caused byover-based Ca-sulfonate, and that the decrease in theboundary friction was caused by over-based Ca-sul-fonate and FMs. INTRODUC