400 Commonwealth Drive, Warrendale, PA 15096-0001 U.S.A. Tel: (724) 776-4841 Fax: (724) 776-5760 Web: www.sae.org SAE TECHNICAL PAPER SERIES 2002-01-1695 Low and High Temperature Non-Newtonian Behavior of Automatic Transmission Fluids Reuben Sarkar General Motors Powertrain Mark T. Devlin, Shoutian Li, Michael B. Glasgow and Tze-Chi Jao Ethyl Petroleum Additives Inc. International Spring Fuels & Lubricants Meeting & Exhibition Reno, Nevada May 6-9, 2002Downloaded from SAE International by Brought to you by the University of Kansas (Technical reports: 1998 to Present), Monday, September 24, 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 per article copy fee through the Copyright Clearance Center, Inc. Operations Center, 222 Rosewood Drive, Danvers, MA 01923 for copying beyond that permitted by Sections 107 or 108 of the 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. 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 wri tten permission of the publisher. ISSN 0148-7191 Copyright © 2002 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 pu blished 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 300 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 Brought to you by the University of Kansas (Technical reports: 1998 to Present), Monday, September 24, 20182002-01-1695 Low and High Temperature Non-Newtonian Behavior of Automatic Transmission Fluids Reuben Sarkar General Motors Powertrain Ethyl Petroleum Additives Inc. Copyright © 2002 Society of Automotive Engineers, Inc. ABSTRACT Rheological properties of automatic transmission fluids (ATFs) are typically characterized by their kinematic (ASTM D 445) and Brookfield (ASTM D 2983) viscosities. However, ATFs contain polymeric viscosity modifiers, which often result in non-Newtonian fluid behavior as the polymers align and stretch under the shear stresses experienced in automatic transmissions. Therefore, the standard rheological tests, which are normally run under low shear stresses , may not adequately characterize an ATF's flow properties under the operating conditions of the automatic transmission. This study was designed to characterize the rheological properties of ATFs containing different amounts of viscosity modifiers, different base oil types and different levels of permanent shear stability under the shear and temperature conditions which exist in automatic transmissions. The results indicate that fluids with the same kinematic and Brookfield viscosities can have viscosities under typical transmission operating conditions that differ by as much as 40%. INTRODUCTION The rheological properties of lubricants in general have been extensively studied, since these properties control a lubricant