400 Commonwealth Drive, Warrendale, PA 15096-0001 U.S.A. Tel: (724) 776-4841 Fax: (724) 776-5760 SAE TECHNICAL PAPER SERIES 2001-01-0871 New Five-Speed Automatic Transmission for FWD Vehicles Yoshihisa Yamamoto, Masaaki Nishida, Kenji Suzuki, Masao Saitou and Hiroshi Tsutsui Aisin AW Co., Ltd. Shigeyasu Kozaki AW Technical Center U.S.A., Inc Reprinted From: Transmission and Driveline Systems Symposium 2001 (SP–1598) SAE 2001 World Congress Detroit, Michigan March 5-8, 2001Downloaded from SAE International by Big Ten Academic Alliance, Tuesday, July 31, 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 2001 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 theGlobal Mobility DatabaseDownloaded from SAE International by Big Ten Academic Alliance, Tuesday, July 31, 2018 1 2001-01-0871 New Five-Speed Automatic Transmission for FWD Vehicles Yoshihisa Yamamoto, Masaaki Nishida, Kenji Suzuki, Masao Saitou and Hiroshi Tsutsui Aisin AW Co., Ltd. Shigeyasu Kozaki AW Technical Center U.S.A., Inc Copyright © 2001 Society of Automotive Engineers, Inc. ABSTRACT AISIN AW has developed a five-speed automatic transmission “55-50SN” for front wheel drive (FWD) vehicles. This new 55-50SN has been developed with a concept to minimize length and mass increase compared with the current four-speed automatic transmission, and is one of the most compact five-speed automatic transmissions in the world. This has been accomplished by newly developed planetary gear sets, a new differential, and a new squeezed torque converter. In addition, the control system is made by a unique design to maintain the excellent compactness and to achieve a high quality smooth shift feeling. This paper describes the construction, characteristic, and function of this five-speed automatic transmission. INTRODUCTION More than 10 years have passed since the four-speed automatic transmission became the main automatic transmission in the world. Aisin AW’s four-speed automatic transmission “50-40LE”(1)* and “50-42LE” announced in 1988 was an advanced automatic transmission at that time, but has been losing its competitive position.