400 Commonwealth Drive, Warrendale, PA 15096-0001 U.S.A. Tel: (724) 776-4841 Fax: (724) 776-5760 SAE TECHNICAL PAPER SERIES 981447 An Experimental Investigation of Lubricant/Main Shaft Interaction and Dryout in an Automatic Transmission Model Sun-Wen Cheng and Wen-Jei Yang University of Michigan Ching-Chung Ling Ford Motor Co. Reprinted From: Lubricants for Passenger Cars and Diesel Engines (SP-1368) International Spring Fuels and Lubricants Meeting and Exposition Dearborn, Michigan May 4-6, 1998Downloaded from SAE International by University of Wisconsin - Madison , Sunday, September 09, 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 1998 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 Wisconsin - Madison , Sunday, September 09, 20181981447 An Experimental Investigation of Lubricant/Main Shaft Interaction and Dryout in an Automatic Transmission Model Sun-Wen Cheng and Wen-Jei Yang University of Michigan Ching-Chung Ling Ford Motor Co. Copyright © 1998 Society of Automotive Engineers, Inc. ABSTRACT When unexpected integrated lubricant-related problems occur, for example, high-speed operating conditions,lubricants can be degraded and even fail to reach certainautomatic transmission parts. Dryout of oil films means aserious lack of lubrication, which may damage the powertransmission line and key parts. Dryout of ATF is analo-gous to that in forced convective boiling and condensa-tion. It thus requires special efforts to determine themechanics that induce such fluid transport phenomena.This paper presents an experimental investigation oflubricant activities in the main shaft. Dimensional analy-sis is applied, and flow maps of the air-oil flow and dryoutregimes are constructed. Correlations closely agree withthe data and reveal the possibility of dryout. Heat trans-fer effect is briefly discussed. INTRODUCTION Lubricating oils are viscous and primarily used in bothintermittent and continuous services (Speight, 1991).The latter case, including ATF, works under various oper-ating conditions so that the physica