Трансмиссия Turbo Hydramatic 125C: особенности и проблемы с соленоидом блокировки гидротрансформатора.

The Turbo Hydramatic 125 was the first in a line of automatic transmissions from General Motors designed for transverse engine application. Introduced in 1980, the line evolved into today's 4T40/45/65/80 line.

This was a later model of the 125 that debuted for 1982 and included a torque converter clutch or TCC. The TCC acts similar to a clutch in a manual transmission vehicle, in that at speeds above 35 MPH a combination of engine vacuum and temperature sensing valves, and a dedicated brake switch and in later models an ECU activated a solenoid which engaged a clutch physically locking the impeller and turbine inside the torque converter together causing engine power to be transferred directly to the transaxle. The C in Turbo Hydramatic 125 C denoted the use of a TCC. The solenoid that controls this is notorious for failure due to overheated plastic componentry, and problems indicated by an engine stall when stopping from speeds greater than 55 MPH. This occurs because the clutch does not disengage, and as the affected vehicle's speed nears zero miles per hour, the engine is forced to decelerate to zero rpm.

For the 1988 model year, the Pontiac Division of GM utilized a THM 125C modified to accommodate a full time All Wheel Drive planetary gear transfer case and output housing to send 40% of the output torque to the rear wheels in the 3.1 liter powered 6000STE. While a similar design was used for the later 4T65E, the three speed design was utilized for only three model years, after which all wheel drive was discontinued as an option for the car line.