Production of the U660E and U660F commenced in January 2006, Toyota's first 6-speed automatic transaxles for front-wheel-drive vehicles; transaxles feature a compact gear train that achieves six speeds using a single axis to produce a high torque of 400 Nm, and are as low cost, compact, and light as 4-speed automatic transaxles[1] The transaxle is a Lepelletier design which uses a simple gear set to drive a Ravigneaux planetary gear set (with long and short pinion gears in the same planet carrier).[2]
U660E
6 speed automatic transverse (V6) 6 speed version of the U151E and F
6 speed automatic communicates with engine to calculate torque with reduced-friction clutch and thrust bearings multi-mode automatic transmission, electronically controlled transmission with intelligence (ECT-i).
Production of the UA 80E and UA 80F commenced in August 2016. This transaxle features a compact gear train that achieves eight speeds using a single axis allowing for input torque up to 430Nm. It is a more compact and optimized version of the U880 automatic transmission structure with additional features for improved performance and efficiency. The marketing name for the transmission is the "Direct Shift – 8AT 8-speed automatic transmission"[3][4] Unlike the UB 80 transmission, which was developed for Toyota by Aisin AW, the UA 80 was developed in a joint venture between Toyota and Aisin AW. Due to global application, development was done in a global fashion involving engineering resources in both Japan and the US. The UB 80E/F transmissions are used for lower torque applications, 4 cylinder engines, and rated at 280 N⋅m (207 lb⋅ft).[5]
^Differences in gear ratios have a measurable, direct impact on vehicle dynamics, performance, waste emissions as well as fuel mileage
^Logically, the gearset concept (layout) provides for this 2nd reverse gear, but it will most likely not be used in the transmissions that the car manufacturers eventually bring to market. In some data sheets, the gear ratio of R2 is given, presumably a careless error
UA80 E/F Drivability Complaints and Subsequent Lawsuits
Owners of 2017 and up Highlanders and Sienna models starting experiencing noises, harsh shifts, malfunction indications and reduced power. These issues lead to several Class Action lawsuits which prompted Toyota to issue numerous TSBs and the ZJC Customer Support Program.[6][7] The ZJC Customer Support Program only covers a small number of 2017 & 2018 UA80 transmissions.
Similar, if not the same, issues that the ZJC Customer Support Program cover continue to occur in later model years of Highlander and Sienna models. This is leaving customers to believe the scope is larger than what Toyota is indicating.[8]
In December 2024, Gears Magazine published an article shedding some light into the cause of the UA80 drivability issues.[9] The main focus is the drive gear assembly support bearing area where the retaining nut comes loose and allows the transfer gear to move.
