840049 Toyota New Four-Speed Automatic Transmission for Front Wheel Drive Vehicles Koujiro Kuramochi, Kazuhiko Shindo, and Seitoku Kubo Toyota Motor Corp. Masakatsu Miura Aisin-Warner Limited International Congress & Exposition Detroit, Michigan February 27-March 2,1984 Downloaded from SAE International by University of British Columbia, Tuesday, September 25, 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 the stated per article copy fee through the Copyright Clearance Center, Inc., Operations Center, P.O. Box 765, 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 collective works, or for resale. Papers published prior to 1978 may also be copied at a per paper fee of $2.50 under the above stated 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. Downloaded from SAE International by University of British Columbia, Tuesday, September 25, 2018840049 Toyota New Four-Speed Automatic Transmission for Front Wheel Drive Vehicles Koujiro Kuramochi, Kazuhiko Shindo, and Seitoku Kubo Toyota Motor Corp. Masakatsu Miura Aisin-Warner Limited ABSTRACT The design requirement for more efficient vehicle moves a compact car toward front wheel drive arrangement, which requires an entire redesign of its power train. Toyota, with systematic approach from its planning stage, has developed a new automatic transmission series including one 3-speed and two 4-speed transmissions. An extensive examination on gear train arrangements enabled the 3-speed light, compact and highly reliable under the arrangement of Simpson gear train, and freewheel shifts with one-way clutches at every shifting. Two different 4th gear packages with freewheel shift are combined with the 3-speed unit to provide the versatility for the 4-speed units in various installations. Besides, these trans- aissions feature lock-up clutch converter, oil pump of a new tooth profile and two different control systems: hydraulic and electro- hydrauie. MARKET DEMANDS FOR ALL AUTOMOBILE became diver­ sified and sophisticated in various aspects such as fuel economy improvement with efficient power train, compactness, weight reduction, better comfort with more interior space and improvement of driving performance. To meet these contradictory requirements, there is a rapid progress underway on development of a front wheel drive (FWD) vehicle with the trans­ verse engine arrangement. The arrangement of the power train, among all, plays an important role to maximize advan­ tages of the FwD vehicle. Because of this, most of the engineering efforts was exerted at the planning stage of the vehicle. On the other hand, continuous efforts to improve a rear wheel drive (RWD) car realised a transmission system which improved the fuel economy, driving performance and also noise reduction. Specifically, an overdrive 4-speea automatic transmission was developed in 1977 for the first application to a small passenger car, followed by an introduction of 4-speed automatic transmission with lock-up converter in 1980. Significant effects brought by these two 4-speed transmissions became apparent, making the 4-speed a mainstream of the transmission variants in Toyota cars; the comparable figure in production be