4T40-E/4T45-E Transmission Features & Benefits
OVERVIEW
The Hydra-matic 4T40-E is an electronically controlled four-speed lauded for its high quality, smooth shifting and quiet operation. With a wider chain and other more robust components, the 4T45-E variant has upgraded torque capacity over the 4T40-E. Both units are engineered for light weight, maintenance-free convenience and outstanding fuel economy.
NEW OR CHANGED FOR 2001 MODEL YEAR
Carry over model year, minor cost and quality improvements only.
HISTORY
The 4T40-E transaxle was first introduced in the 1995 Chevrolet Cavalier and Pontiac Sunfire, mated to the 2.3-liter Quad 4 engine, and was instantly recognized as one of the premiere powertrains in its class. The stronger 4T45-E first appeared in 1999 in the 3400 V6-equipped Pontiac Grand Am and Oldsmobile Alero. Over the past several model years, much of the heavy-duty componentry of the 4T45-E has been applied to the 4T40-E in an effort to commonize production processes as much as possible, thereby improving durability while reducing costs.
SMOOTH OPERATION
Smooth shifting is attained through the use of a Powertrain Control Module (PCM). The PCM monitors engine operation and environmental factors such as altitude and temperature, and sends electronic signals to variable-bleed solenoids that change hydraulic line pressure and shift timing, thus adjusting the operation of the transaxle. The result is a seamless link between the engine, transaxle and vehicle.
QUIET OPERATION
The 4T40-E / 4T45-E transaxles employ a host of noise-reducing features including: high helix angle fine pitch gear sets; specially balanced internal components to reduce vibration; and a random-pattern chain which reduces pure tones, which are more readily noticed by the driver.
FUEL EFFICIENCY
Notable features include the use of four widely-spaced gear ratios, an optimally sized variable-capacity vane pump, roller thrust bearings for reduced friction, and a low-friction rocker pin chain, all of which contribute to maximum efficiency, leading to impressive fuel economy.
LIGHTWEIGHT
World-class mass efficiency (low weight when compared to torque capacity) is attained through a number of weight-saving measures, including: a simple chain-transfer, two-axis configuration; thin-wall castings strengthened with strategically placed supporting ribs; lost-foam castings of key components; widespread use of special light-weight composite materials. Overall low mass is another important contributor to fuel economy.
LOW MAINTENANCE
The 4T40-E / 4T45-E use long-life DEXRON-III transmission fluid, which does not require fluid or filter change, (except for under certain driving conditions as outlined in the Owner's Manual.) Additionally, the PCM monitors operating conditions of the transaxle and alerts the driver with a warning light if there is a deterioration that would cause the vehicle to exceed acceptable emissions levels, in compliance with OBD II regulations.
