'&: ^:Ww-'^^^' ^ ■^^•m^mm m m--^:- SOCIETY OF AUTOMOTIVE ENGINEERS, INC. 485 Lexington Avenue, New York, N. Y. 10017 ATF-TYPE F Keeps Pace with Fill-for-Life Requirements W. D. Ross and B. A. Pearson M Transmission and Chassis Division FORD MOTOR COMPANY : jdfejj-i^i-.; SOCIETY OF AUTOMOTIVE ENGINEERS Automotive Engineering Congress Detroit, Mich. January 8-12,1968 Downloaded from SAE International by University of Edinburgh, Sunday, August 26, 2018ATF-TYPE F Keeps Pace with Fill-for-Life Requirements By W. D. Ross and B. A. Pearson Transmission and Chassis Division FORD MOTOR COMPANY BACKGROUND From 1949 to 1960, most passenger car automatic transmissions required the use of Type A or Type A Suffix A (1)* automatic transmission fluid. Although these fluids were not completely adequate for all transmissions, they were much better than engine oils, mineral oUs or other fluids which had been used in this application. Factory fill fluids at Ford were required to meet the Ford M2C33-A-B (2) specification, which described essentially a Type A Suffix A fluid. ** LIFETIME FILL In 1958, "lifetime fUl" for Ford automatic transmissions was established as an objective in fluid development at Ford Research. It was doubtful that either the Type A Suffix A or the M2C33-B specification could be used to de­ scribe a fluid for "lifetime fill," since relatively short drain intervals were required by auto manufacturers recommending the use of these fluids. Two other factors indicated inadequacy of these specifications for describing" fill-for-life" fluid. First, increasing loads were being im­ posed on the automatic transmission fluid due to such factors as greater traffic density, in­ creasing use of passenger cars for trailer towing, and increasing use of higher power engines. Also, a large number of formulations had been developed for meeting the Type A Suffix A specification, some of which exhibited excellent performance in service, while others did not. For these reasons Ford began a pro - gram to secure a fluid possessing character­ istics necessary for long term service. * Numbers in parentheses designate References at end of paper. ** In Ford specifications, M2C33-A-B, M2C33-C-D, and M2C33-E-F, the first suffix letter refers to natural un-dyed fluid and the second to red-dyed fluid. Hereafter only the red-dyed fluid designations, B, D, and F will be used. ABSTRACT The development of the Ford Automatic Transmission Fluid from specification M2C33-B, through M2C33-D, to the new M2C33-F specification is traced. Requirements of the new specifica­ tion and reasons for the change are discussed. Some experiences with the "fill-for-life" policy over the years from 1960-1967 are cited. Downloaded from SAE International by University of Edinburgh, Sunday, August 26, 2018M2C33-D FLUIDS A fluid was eventually developed which exhibited significant improvement in minimiz­ ing the harmful effects of oil oxidation, as measured by sludge and varnish formation in a Merc-0-Matic Oxidation Test, (3) and of­ fered improved wear protection for planetary gearset needle bearings and power steering pumps. In addition, when tested with the modi­ fied 4-ball friction apparatus (3) (4) with steel rubbing on sintered bronze clutch facing mate - rial specimens, it was noted that the friction sliding speed curves at 200° F were not like those for the M2C33-B (5) fluids, with their low static coefficients, but instead, yielded high static coefficients and low dynamic coefficients similar to those of non- additive treated mineral oils. At the same time, a program was in progress to develop clutch friction materials with higher static capacity than sintered bronze materials, thus, this new high static friction fluid was of immediate interest. The modified 4-ball (3) friction character­ istics of this new fluid, candidate " M", and an M2C33-B fluid, "P" are compared in Figure 1.* FRICTION - SL