Originally Posted by
Smittro
The 4T60-E (and similar 4T65-E) is a series of automatic transmissions from General Motors. Designed for transverse engine configurations, the series includes 4 forward gears. The 4Txx family is an evolution of the original Turbo-Hydramatic 125 transverse automatic introduced in the late 1970s.
The "-E" transmission is electronically controlled and features an automatic overdrive transaxle with an electronically controlled torque converter clutch.
The 4T65 is built at Warren Transmission in Warren, Michigan
The 4T60 was the transitional model from the old Hydramatic (formerly called the 440-T4 aka 4T60) to the new electronically-controlled transverse family. Introduced in 1984 on the 1985 C-bodies, it was enhanced with electronic controls to become the 4T60-E in 1991. By the mid-1990s, the 4T60-E was the transmission of choice in nearly every front-wheel drive GM vehicle. A heavy-duty 4T60-E HD was produced only in 1996 for the supercharged GM 3800 engine. The 4T60-E was phased out in favor of the 4T65 beginning in 1997.
The 4T60-E featured a 245mm torque converter with varying stall speed and gear ratios. Stall speed is the rpm(revolutions per minute) that the converter reaches maximum efficiency and is correlated with the engine and vehicle weight for the best combination of power and efficiency for the vehicle. (For example a '95 Beretta features a 1650rpm stall converter as opposed to '99 Century converter with a stall of 2095rpm.) Gear ratios are remarkable in the 4T60 family in that there are two points in which the transmission can have different gearing (the drive-chain sprockets and the differential, or Final Drive) resulting in up to 12 different available gear ratios. The combined gearing of the two is called the Overall Axle Ratio, and the different ratios allow the use of the transmission in multiple applications based on the engine and vehicle. Please note then that there are up to 12 different versions of the 4T60-E, and they should not be mixed as undesired operation would occur.
Gear ratios:
2.92
1.56
1.00
0.70
2.38