2010 Hydra-Matic 4T80 (MH1)
Hydra-Matic 4T80 four-speed electronically controlled FWD automatic Car transaxle
2010 Model Year Summary
Carryover features and benefits from 2009 model year
Low maintenance
Two factors contribute to the low maintenance capability of the 4T80, which requires no service or fluid changes under normal operating conditions. First is the robustness of the design of the 4T80, and second is the quality of assembly. The transmission fluid, DEXRON® VI, was developed to have a more consistent viscosity profile; a more consistent shift performance in extreme conditions; and less degradation over time. Internal GM tests have demonstrated DEXRON® VI to deliver more than twice the durability and stability in friction tests compared to existing fluids.
Overview
Introduced in the 1992 Cadillac Allante technology leader platform, the Hydra-Matic 4T80 remains one of the most robust front-wheel drive transaxles in the world. Supporting that statement is the transmission’s outstanding record of long-term durability. In 2005 the transaxle replaced its viscous torque converter lock-up clutch with the GM proprietary ECCC system, which dampens engine torque pulses and provides a smooth engagement of torque converter lock-up. It can also be tuned to lock the torque converter as early as possible during acceleration to increase fuel economy.
The 4T80 is used in Cadillac and Buick full-size sedans, and the internal performance characteristics of the torque converters have been optimized for unique response characteristics of the 4.6L V8 Cadillac DTS and Buick Lucerne.
The 4T80 is a two-axis conventional four-speed automatic transaxle, with electronic controls. It uses freewheel clutches to engage the forward ratios, and has outstandingly smooth shifts. Continual improvements have kept the 4T80 a leader in smooth-shifting and torque-handling capabilities. Reliability improvements have also been continual.
For the 2006 Model Year, the PCM (powertrain control module) was replaced with the ECM/TCM (engine control module / transmission control module), and that required the internal wire harness to be revised. These modules allow sophisticated electronic programming for shift performance, optimizing fuel economy and other functions.
