Editing Automatic transmission (section)

====1965–present: increased ratio count and electronics====
By the late 1960s, most of the fluid-coupling two-speed and four-speed transmissions had disappeared in favor of three-speed units with torque converters. Also around this time, [[whale oil]] was removed from the automatic transmission fluid.<ref>{{cite web|url=http://www.machinerylubrication.com/article_detail.asp?articleid=392 |title=Almost Burned |website=www.machinerylubrication.com |archive-url=https://web.archive.org/web/20070927082224/http://www.machinerylubrication.com/article_detail.asp?articleid=392 |archive-date=27 September 2007}}</ref> During the 1980s, automatic transmissions with four gear ratios became increasingly common,<ref>{{cite web |title=U.S. Patent 5370589 |url=http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.htm&r=1&p=1&f=G&l=50&d=PTXT&S1=5370589.PN.&OS=pn%2F5370589&RS=PN%2F5370589 |website=www.patft.uspto.gov |archive-url=https://web.archive.org/web/20130514181727/http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.htm&r=1&p=1&f=G&l=50&d=PTXT&S1=5370589.PN.&OS=pn%2F5370589&RS=PN%2F5370589 |archive-date=14 May 2013 |url-status=dead}}</ref> and many were equipped with lock-up torque convertors in order to improve fuel economy.

[[Electronics]] began to be more commonly used to control the transmission, replacing mechanical control methods such as spring-loaded valves in the valve body. Most systems use [[solenoid]]s which are controlled by either the [[engine control unit]], or a separate [[transmission control unit]]. This allows for more precise control of shift points, shift quality, lower shift times and manual control.

The first five-speed automatic was the [[ZF_5HP_transmission|ZF 5HP18 transmission]], debuting in 1991 on various [[BMW]] models. The first six-speed automatic was the [[ZF 6HP26 transmission]], which debuted in the 2002 [[BMW 7 Series (E65)]]. The first seven-speed automatic was the [[Mercedes-Benz 7G-Tronic transmission]], which debuted a year later. In 2007, the first eight-speed transmission to reach production was the [[Toyota A transmission#AA80E|Toyota AA80E transmission]]. The first nine-speed and ten-speed transmissions were the 2013 [[ZF 9HP transmission]] and 2017 ''Toyota Direct Shift-10A'' (used in the [[Lexus LC]]) respectively.