930669 General Motors All New Electronic Transverse FWD Automatic Transaxle (4T80-E) Stephen R. McKenny, Peter Mack, Steve R. Saia, and Steve Whitney GM Powertrain Div. Reprinted from: Automotive Transmissions and Drivelines (SP-965) International Congress and Exposition Detroit, Michigan March 1-5, 1993 Downloaded from SAE International by University of New South Wales, Monday, September 17, 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 specific clients. This consent is given on the condition, however, that the copier pay a $5.00 per article copy fee through the Copyright Clearance Center, Inc. Operations Center, 27 Congress St., Salem, MA 01970 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. SAE routinely stocks printed papers for a period of three years following date of publication. Direct your orders to SAE Customer Sales and Satisfaction Depart- ment. 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 by reproduced in any form, in an electronic retrieval system or otherwise, without the prior written permission of the publisher. ISSN 0148-7191 Copyright 1993 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 published 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 Activity Board, SAE. Printed in USA 90-1203B/PG Downloaded from SAE International by University of New South Wales, Monday, September 17, 2018930669 General Motors All New Electronic Transverse FWD Automatic Transaxle (4T80-E) Stephen R. McKenny, Peter Mack, Steve R. Saia, and Steve Whitney GM Powertrain Div. ABSTRACT The new 4T80-E automatic transmission from General Motors is a high torque, high speed, electronically controlled front wheel drive transaxle. This completely new transmission was developed for use with the new Cadillac 32 valve Northstar V-8 engine. Significant aspects of this transmission include software, hardware, and systems features to provide high durability, high torque, high shift speeds, smooth shifts, a wide ratio spread, low noise, high efficiency, leak prevention, and synchronous manufacturing. INTRODUCTION This paper describes the major features of the Hydra-matic 4T80-E transmission. It also highlights some aspects of the development process and manufacturing system. This transmission operates at maximum torque and speed levels which exceed previous transverse front wheel drive automatics. Performance and packaging requirements led to a 'clean sheet' integral four speed design with a new converter and the latest generation electronic controls. Since the 4T80-E was designed for luxury cars, customer satisfaction was a very high priority. The transmission has several features to ensure very good driveability and very smooth shifts. It was designed to accommodate equal length drive axles to minimize torque steer. All freewheel shifts were used to provide precise control of shift feel via control of a single element fo