2010Hydra-Matic 4T45 (MN5, ME7 Hybrid )
- 2010Model Year Summary
Hydra-Matic 4T45 four-speed FWD electronically controlled automatictransmission.
There are no planned performance upgrades for the 2010 Model Year, activities will be centered on quality improvements
FULL DESCRIPTIONS OF FEATURES AND BENEFITS
Low maintenance
The 4T45 transaxle uses DEXRON® VI fluid, and is "fill-for-life", with no maintenance scheduled for normal operation. DEXRON® VI, was developed to behave more consistently during temperature and other environmental variations, as well as to provide even lubrication of the moving surfaces of the transmission and more stable shift performance in extreme conditions. Durability is also increased with the new fluid.
Overview
The Hydra-Matic 4T45 ( MN5 ), is an electronically controlled four-speed transaxle that achieves industry benchmark levels of reliability and shift quality. Precisely calibrated electronic controls enable the transmission to adapt to a variety of driving conditions providing the driver with consistent shift quality. All 4T45 transaxles use the proprietary GM ECCC (Electronic Controlled Capacity Clutch) technology for torque converter lock-up functions. ECCC allows a very small degree of controlled slip in the torque converter lockup clutch to isolate drivetrain pulses and contribute to smooth delivery of power.The transaxle's low-noise operation is a result of the high helix angle gears, an enclosed bell housing, and the random-pattern chain. Mass has been reduced through optimized case design and use of lightweight materials. Driver Shift Control (DSC) function is available that allows easier manual shifting of the gear ranges. On some models the floor-mounted shift lever can be moved rearward and to the right to enable the DSC, and momentary movements of the lever forward and rearward can respectively upshift and downshift the transaxle. Electronic controls prevent downshifting at speeds which would cause the engine to over-rev, and automatically downshift when the vehicle comes to a stop. The 4T45 has a modified channel plate and valve body which allows the ability to electronically change shifts as signaled by the driver pushing a switch on the gear selector lever. To use the feature in the Malibu application, for example, the driver shifts the gear selector from D to the D3 position, then pushes the selector switch to downshift to D2 and then D1. Upshifting from D1 to D2 and D3 is accomplished through the selector switch as well.
On the 4T45 ( ME7 ), hybrid applications, there are several different operating conditions, including an engine-off condition while the vehicle is stopped at a stoplight, battery recharge on deceleration, and electric motor assist on acceleration. To accommodate the electric motor and the duty cycle of engine-off operation, the 4T45 has been modified to enable normal operation by utilizing an electrically powered hydraulic auxiliary pump to maintain pressure to the Forward clutch. The Pressure Switch Manifold has also been modified for additional diagnostic capability..