nte Engineering Society ** =For Advancing Mobility rand Sea ~ir and space, INTERNATIONAL^ 400 COMMONWEALTH DRIVE, WARRENDALE, PA 15096-0001 U.S.A. Determining Frictional Performance of Automatic Transmission Fluids in a Band Clutch Russell F. Stebar, Ellard D. Davison and James L. Linden Fuels and Lubricants Dept. General Motors Research Laboratories International Fuels and Lubricants Meeting and Exposition Tulsa, Oklahoma October 22-25,1990 Downloaded from SAE International by University of Leeds, Sunday, August 12, 2018The appearance of the 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 specli clients. This consent is given on the condition, however, that the copier pay a $5.00 per articlecowfee through the Copyright Clearance Center, Inc., Operations Center, 27 Congress St., Salem, MA 01 970 for copying beyond that permitted by Sedions 1 O7or 108 ofthe U.S. Copyright Law. This consent does not extend to other kinds of copying such as copying 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 Service Department. To obtain quantity reprint rates, 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 writ- ten permission of the publisher. ISSN 01 48-71 91 Copyright 1990 Soclety of Automotive Englneers, Inc. Positions and opinions advanced in this paper are those of the Persons wishing to submit papers to be ansidered for presen- author(s) and not necessarily thoseof SAE. Theauthor issolely tation or publication through SAE should send the manuscript responsible for the content of the paper. A process is available or a 300 word abstract of a proposed manuscript to: Secretary, by which discussions will be printed with the paper if it is Engineering Adivity Board, SAE. published in SAE Transactions. For permission to publish this paper in full or in part, contact the SAE Publications Division. Printed In USA Downloaded from SAE International by University of Leeds, Sunday, August 12, 2018Determining Frictional Performance ABSTRACT Frictional characteristics of several automatic transmission fluids (ATF's) were evaluated in an SAE No. 2 Friction Machine adapted to the band clutch from a front-wheel-drive, three-speed automatic transaxle. The bench test apparatus subjects the band clutch to repeated engagements (24 000 in a 100-hour test period) at elevated temperature with representative clutch energy dissipation and lockup time, and with forced aeration of the fluid. Fluid frictional performance is judged from the level and stability of friction torque during the 24 000 clutch engagements. The test is repeatable and readily distinguishes fluids having different frictional characteristics. Fluid frictionai behavior in the band machine is shown to reflect fluid effects on shift performance in an engine dynamometer, transaxle cycling test. Also, fluid effects determined in the cycling test are shown to match those obtained in a vehicle. Both shift quality and durability can be inferred from the band friction machine results. MANY MODERN AUTOMATIC TRANSMISSIONS and transaxles utilize power-shifting band clutches to implement gear-ratio changes. The band clutch is widely used because it can provide packaging and cost advantages over the multiple-plate clutch. However, satisfactory lubrication of the band clutch presents a challenge for several reasons: 1) unit energy loading is quite high, typically about three times that for a plate clutch; 2) the load issue is further aggravat