c I&P-1 The Engineering Society mr=* For Advancing Mobility Ii2i_Z7 Land Sea Air and Space 400 COMMONWEALTH DRIVE WARRENDALE, PA 15096 870356 James L. Linden and Steven P. Kemp Fuels and Lubricants Dept. General Motors Research Labs Warren, M! International Congress and Exposition Detroit, Michigan February 23-27,1987 Downloaded from SAE International by University of Leeds, Monday, September 24, 2018The appearance of the code at the bottom of the first page of this paper indicates SAE's consent that copies of the paper may be made for persona! or internal use, or for the personal or internal use of specific clients. This consent is given on the con­ dition, however, that the copier pay She stated per article copy fee through the Copyright Clearance Center, inc.. Operations Center, P.O. Box 76S, Schenectady, N.Y. 12301, 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 coilective works, or for resale, Papers published prior to 1978 may also be copied at a per paper fee of S2.50 under the above slated conditions. SAE routinely stocks printed papers for a period of three years following date of publication. Direct your orders to SAE Order Department. To obtain quantity reprint rates, permission to reprint a technical paper or per­ mission to use copyrighted SAE publications in other works, contact the SAE Publications Division. AllSAL fvpen Cff abitrzctrd ami Indexed lit (he SAL' Gfoba} Mobility Otfabii? SAE GLOBAL MOBILITY DATABASE No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior written permission of the publisher. ISSN 0148-7X91 Copyright © 1987 Society of Automotive Engineers, Inc. This paper is subject to revision. Statements and opinions ad- Persons wishing to submit papers to be considered for pre- vanced in papers ot discussion axe the author's and are his sentation or publication through SAE should send the manu- responsibility, not SAE's; however, the paper has been edited script or a 300 word abstract of a proposed manuscript to: by SAE for uniform styling and format. Discussion will be Secretary, Engineering Activity Board, SAE. printed with the paper if it is published in SAE Transactions. For permission to publish this paper in fulJ or in part, contact Printed in U.S.A. the SAE Publications Division. Downloaded from SAE International by University of Leeds, Monday, September 24, 2018870356 at Low Temperature with Reducei a a ABSTRACT The effects of automatic transmission fluid viscosity on the low-temperature performance of a front-wheel-drive transaxle were determined in a cold room maintained at a temperature of -20°F (-28.9°C), using both a cranking apparatus and a vehicle. Cranking and vehicle tests were con­ ducted to determine the effects of fluid viscos­ ity on the power required to crank a transaxle and on transaxle performance under low-tempera­ ture transient operation, respectively. Four automatic transmission fluids were tested, rang­ ing in viscosity from 2 800 to 16 000 cP at - 20°F. All test fluids contained the same additive package and were blended using the same types of base oils. Reducing fluid viscosity from 6 000 cP (current factory-fill) to 3 900 cP at -20"F reduced shift times by 10 percent, forward clutch engagement time by 25 percent, apply pressure rise times by 40 percent, and cranking loads by almost 40 percent. Fluids providing such improved low-temperature performance are needed for planned future automatic transmission fluid specifications. ONE OP THE MOST IMPORTANT physical characteris­ tics of automatic transmission fluids (ATF) is viscosity. High-temperature (350°F) viscosities must be high enough to preclude leaking past seals, 0-rings, gaskets, etc., and low