Abstract
The single recent event that has most significantly changed the way in which automotive transmission fluids are defined took place in 1990 when General Motors published its Dexron HE specification. This represented the first major modification of General Motors' Automatic Transmission Fluid (ATF) specifications since July 1978. (The original Dexron II specification was first published in 1973.) The driving force behind the timing for the introduction of this specification was the launch, in 1991, of the Buick Park Avenue with a newly redesigned, electronically‐controlled version of the older Hydramatic 440‐T4 Front‐Wheel‐Drive (FWD) automatic transaxle. This unit was designated the 4T‐60E. The majority of designers of computer‐controlled transmissions use electro‐hydraulic solenoid valves to open and close hydraulic circuits to make the transmission shift. For this reason, many of the new transmission designs require ATFs to have superior low‐temperature fluidity properties. Dexron IIE calls for fluids having a −40°C Brookfield viscosity of less than 20,000 cP, compared with the 50,000 cP requirement of the Dexron II. Only fluids approved to the new specification will be officially endorsed by GM from January 1993.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.